SMALL REEF AQUARIUM BASICS Introduction The interest in Reef Aquariums has recently grown in popularity so rapidly, that everyone, including Pet Store Owners and personnel, have a hard time keeping up with all the developments that are occuring. New filtration methods, and new equipment, appear in the magazines, and in advertising, every month. Newer methods for keeping such aquariums, including very hi-tech instrumentation, are being advocated all the time. Sophisticated testing is recommended as well. In short, a completely different approach than the one Hobbyists and Stores have been accustomed to, leading to a lot of confusion and misunderstandings, especially since some of the recommendations have not been tested over long periods of time yet, and may even conflict. Although books such as "The Marine Fish and Invert Reef Aquarium", and "Advanced Reef Keeping Made Simple" have obviously helped a great deal, both are concerned with larger systems. Tanks in the 100 to 150 gallon range, a size that not many Hobbyists keep and that requires more sophistication, and the related expenses, because of the greater amount of animal life that is kept in such aquariums. Of course, the methods advocated there, can be applied to smaller aquariums as well, but increase the budget required to get into Reef Keeping quite a bit. Many Store Owners, and many Hobbyists, have suggested that I write a book geared more specifically to the Reef Keeper who wishes to maintain a small system successfully without having to spend thousands of dollars. Very instrumental in convincing me to undertake this project was Roger Paro, of Kenlin Pet Supplies, in Mahwah, New Jersey. This manuscript is, therefore, the product of all the suggestions received, and a little arm twisting from some. The book is shorter than my other ones, mainly because interested readers can refer to both of them for a more detailed look at some of the subjects covered here. Additionally, some of the equipment discussed in the other books is not used in the set-up that I would like to suggest for the smaller aquarium, the one discussed here. General aquarium keeping is not covered in this book. You should refer to one of the many other books available for more details on, e.g. heating, biological filtration, and why and how it takes place, stands, tanks, fish, other animals, background information, etc... One such book that is strongly recommended is Martin A. Moe Jr.'s " The Marine Aquarium Reference - Systems and Invertebrates" 1989, 510 pp, Green Turtle Publications. It contains a wealth of information and techniques that you may want to consider when setting up your new Reef Tank, or when making modifications to an existing aquarium. It is brand new and incorporates very up-to-date information, drawing on the latest technology available, and very recent texts, articles and books. Martin Moe's contributions to the Hobby already stood out with his first book, Marine Aquarium Handbook, Beginner to Breeder this one tops it. Every serious Hobbyist should get a copy of it. It is available from stores nationwide. Do not overlook the many books published by T.F.H. Publications either, they are, after all, the largest publishers of Aquarium literature in the world, and have books on many subjects of interest to the Reef Keeping Hobbyist. Your local Pet Store will usually have a wide assortment of their books. What we are trying to achieve in this one, is setting up a Reef Tank on a budget! You may still have to spend more money than what you would lay out for a regular fish tank, but it certainly will not be a budget that resembles anything like the tanks described in both my other books, where most functions are auto- mated; or where I describe how you can introduce such automation, and what your options are. No tank can be set up for two or three hundred dollars, but by following the directions in this guide you should be able to considerably reduce the cost of what you thought installing such a tank would necessitate. The cost of the aquarium and the stand are not part of what we will be reviewing. You may have both already, or you may want to shop around for a special. Pet Stores have them all the time. Alternatively look in your local bargain newspaper. Fish tanks are advertised in such newspapers every week, and at excellent prices. You may even find some of the equipment you will need as well. Because Reef Keeping is complex, much more so than just plain fish-only tanks, the selection of the items that you will be using is important. Buy products that will last you for a long time. Avoid the "store-them-in-the-garage-or-attic and replace- them-with-something-else syndrome" so characteristic of what a lot of us have been doing in the past. By buying the right product, of the right quality, you will buy only once. Let me illustrate this, for example, if you need an overflow surface-skimming syphon, and 3 are offered for sale, don't buy the cheapest one. Unless of course that happens to be the one that you need for your tank. First determine what you need, then select what to buy. If you are looking at running several hundred gallons of water per hour, a syphon with half inch connections will not do the job, even though it may be the cheapest. All that will happen is that after a few weeks you will get tired of messing around with it, having determined that it doesn't really do the job, and end up buying a more expensive one anyway. As a result you end up spending more money than if you had bought the right one to begin with. Determining what your exact needs are is half the battle. Once you know what you need, you can start looking around for the product that meets the specifications you have found to be necessary. That product will not become obsolete in a couple of weeks or months, because it will be the right one for the job. Another example is the redox potential meter. A meter alone will only tell you what the redox is. Soon you may get the urge to control it. A meter cannot do that. You will then want, and need, a redox potential controller. This is a different piece of equipment, that you will then need to buy, and it will obsolete the meter. The money spent on the meter will have been wasted. Think before buying and decide what it really is that you will want to do. Of course, in a small system you may not want to automate, and then a meter will do fine. Ask questions about the equipment. For instance, in the case of controllers, either for pH or redox potential, many less expensive models are so-called "panel mount" types, requiring hard wiring and having no full external cover. What you are probably looking for is a so-called "bench top" model, one in which you can just plug in the device (e.g. ozone, chemical metering pump, peristaltic pump) that you are trying to control, without any wiring whatsoever. Keep these remarks in mind every time you need to acquire some piece of equipment or instrument. They will save you a lot of money in the long run. Reef Keeping is fascinating and it can be great fun, but you must meet certain minimum requirements in water quality, or your tank just will not look good. What these parameters are, and how to attain them on a smaller budget is the purpose of this book. Setting up a Reef Tank will still cost a fair amount of money, but using the methods described here, a lot less than if you went with a full-fledged automated system such as the ones described in my other two books, or often referred to in Marine Reef, the newsletter of which I have the pleasure of being the Editor. Such systems are of course much more self-sufficient, but obviously at a cost. We hope that the recommendations made in this book will help, and welcome suggestions for inclusion in future editions, and reprints. If we have overlooked something, if a particular method has worked for you, let us know about it. Sharing knowledge is what it's all about. As a final note, don't expect any miracles, successful aquarium keeping is a combination of a fair amount of knowledge, common sense practices, and the right equipment. Good luck in your endeavors. Albert J. Thiel Trumbull, Connecticut A special note of thanks to Guido Hueckstedt, whose contributions to the Hobby, and research, are so often overlooked. We also wish to acknowledge : Martin A. Moe and most of all Sarah R. Thiel for her patience and understanding during the writing of this manuscript. Her support was invaluable to me. FILTRATION General Remarks All, or almost all, successful Reef Systems that I have ever seen have one thing in common: they segregate the various modes of filtration required to maintain optimum water quality levels and chemistry. We should try to learn from that empyric evidence, and duplicate the methods used by such successful Reef Keeping Hobbyists. The various segregated methods of filtration that I am referring to here, include the following, most of which you are familiar with to some extent: Mechanical filtration, or fine and micron:sub-micron filtration, to remove so-called detritus or particulate matter from the water, Biological filtration, to break down ammonia, nitrite, and convert the latter to nitrate, Chemical filtration to remove pollutants that the 2 methods mentioned above do not, Foam fractionation, to remove e.g. protein before it breaks down further and pollutes the water, Pressure filters - contact chambers for oxygen and ozone, this includes, for example, oxygen reactors, ozone reactors and such, Miscellaneous methods, e.g. denitrators, specialized resins, tangential flow filters, biomesh filters, aerobic nitrate filters, etc. Some of these will, for obvious reasons, not be used on the small Reef System that we are dealing with in this book: they are meant to be used on more automated systems, and several of them involve quite a considerable expense. Pressurized contact chambers such as oxygen reactors, for instance, can cost around $250.00, and tangential flow filters quite a bit more. Filtration is of course the one important aspect of the total system that determines whether your Reef will be successful or not. It is, indeed, through proper filtration that the water is cleansed of impurities and unwanted compounds and chemicals. This, then, ensures a proper living environment for the fish and invertebrates kept in the tank. Because you add fish, corals and invertebrates, the water quality deteriorates; there is no way around it. A real minimum amount of filtration, that you cannot do without is, as a result, necessary for you to be a successful reef Hobbyist, as it will remove those unwanted noxious elements. Everything ultimately boils down to the quality of the water. The better that quality, the better your Reef Aquarium will look. The worse the water chemistry, the worse the tank will look, and the more life forms will die, which in turn leads to even more problems. Polluted water is the nemesis of every Aquarist. The accumulation of breakdown products of organic and non-organic nature will eventually drop the quality of the water so much, that the tank turns into an environment not suitable for animals. Keep it in mind! And if you do not take care of your system this can happen in a matter of days, sometimes even hours. Fish and invertebrates take the abuse for a while, and then suddenly things will deteriorate very quickly, often to the hobbyist's surprise, as only a few hours earlier everything "seemed" to be fine. Good water chemistry does not happen by chance, it can be attained only in 2 major ways: continuous water changes (the so-called completely open system), or proper and well maintained filtration of at least four kinds, the ones listed higher up, mechanical, biological, chemical and foam fractionation. Fortunately for us, three of these four can nowadays be combined in one unit: the trickle filter. Not all trickle filters on the market, however, offer this feature. If you are in the market for one, check whether the filter that you are looking to acquire incorporates the required filtration steps on one hand, and does so in a segregated fashion on the other, allowing you to control and service mechanical, biological and chemical filtration separately, and in their own right without affecting anything else. Only when such is possible, will you be able to work on your filters to service and maintain them, without affecting what is happening to the others. Mechanical filters need very regular cleaning, chemical filters need to be changed from time to time and rinsed to remove detritus, whereas biological filters should always be left alone. Bacteria in the biological filters (chamber) should not be disturbed by the cleaning process, or by moving the material on which they grow, around or in and out of the filters. Doing so always results in a loss of bacteria, and a considerable reduction in the efficiency of the filters. The latter may result in an increase in ammonia and nitrite and stress to tank life forms. Stress often brings about disease. Usually parasitic disease. The latter is very hard to treat in Reef Tanks, as no copper or similar compounds can be used, because of the invertebrates in the tank. Both stress and disease can rapidly lead to massive outbreaks of parasitic infestations because one infected fish, acting as a host, brings about a rapid multiplication of parasites, which then attack other fish. A real vicious circle which is then very hard to control. Filtration, and how its various components are set up is, therefore, very important for the long time appearance and health of the aquarium. The selection of the components of the filtration system must, as a result, be carefully planned and thought out in advance. Many Hobbyists pay little or no attention to mechanical filtration. That is a considerable mistake. Mechanical filtration is, indeed, an important part of maintaining adequate water chemistry parameters. Biological filtration does get a lot of attention, perhaps too much sometimes. Chemical filtration is going through a growth stage, and more and more Hobbyists are starting to realize its importance, which is an excellent trend, of course. In the subsequent chapters we will take a more in depth look at each of these strongly recommended forms of water filtration, and suggest how they should be incorportated in a small reef aquarium. MECHANICAL FILTRATION Mechanical filtration is nothing more than removing many types of unwanted particulate matter from the system, by first trapping it in a dedicated location (or several such locations), and then cleaning those locations to remove the matter entirely from the tank and filters. Merely moving it from inside the tank, where you can see it floating around in the water, to the filters, does not improve the water quality at all. The only thing such achieves, is removing it from your sight, but not from the water. Leaving particulate matter trapped in the mechanical filters for too long does, in fact, more damage than good, as once the trapped matter is concentrated in a small area, it can quickly deplete large amounts of oxygen from the water. This material may then start decaying in an anaerobic (anoxic - oxygen poor or oxygen depleted) manner. This can quickly add many compounds that are totally undesirable, and dangerous, to the water . These compounds result from break-down by-products. The better known one that you are probably familiar with is hydrogen sulfide, but there are many other such breakdown products that you do not want in the tank's water. Even small amounts of hydrogen sulfide lower the water quality enough, for your lifeforms not to look at their best. Even if the decay that takes place does not remove all the oxygen (which it will in the extreme case), it can still remove considerable amounts, and lower dissolved oxygen to dangerous levels for all animal life you keep in the tank. They may not die, they will more than likely not, but they will just not look as good as they would, if the water quality were better. It is all a matter of degree; the difference between a vibrant looking aquarium, and one that looks all right to you, but does not draw any oh's and ah's from your friends or visitors. Mechanical filtration is, therefore, a two-step process : first you trap the dirt, detritus, floculate, particulate, (all names for what we are trying to remove) in a specially designed area by means of a screen, mesh, cartridge, floss, or other form of filter, and secondly you clean those filters regularly to remove that matter entirely from the system (the mass of water in your tank and filters). Doing so prevents whatever you trapped in the filters from breaking down, causing problems for you by lowering the water quality (usually evidenced by lower dissolved oxygen levels in the water). At the same time, because you prevented the decay, you also prevented the addition of other compounds that result from such decay, to the tank's water. Some of these breakdown compounds may even be more toxic than the particulate matter that you trapped to begin with, obviating the need to clean your mechanical filters on a very regular basis. Once a week, or even more frequently, is strongly recommended. Anything that can trap dirt acts as a mechanical filter, even materials in the tank and filters that you may not think about, e.g. the material used inside the trickle filter's biological filtration area (I am referring to material that is dense, close-meshed, or that packs and restricts the flow of the water, e.g. gravel). Keep this in mind because, often, areas such as those never get cleaned, or they are cleaned much too infrequently. Examples are calcite layers in the bottom of filters, undergravel filters that are in dis-use or are used on a reduced flow rate, etc... Mechanical filters come in many forms. They could be canisters filled with material such as EfiMech from Eheim, or Biomech from Kordon, filter floss, pads, blue-white bonded pads, bags; or they can be specially designed containers with pleated cartridges or bags, and many others still. All work efficiently and will trap lots of detritus. The finer the material, the more it will remove, especially after it has accumulated some dirt already. As the spaces where the water can flow through get smaller, get restricted, finer and finer particles will be trapped. This will slow the flow of water through the material down as well, which is yet another reason why you should clean all such filters regularly. Here is a short overview of the most common types of mechanical filtration methods used, and available to the Hobbyist. You should use at least one of them, but you may want to combine several in your system, for optimum efficiency. CANISTERS (traditional) : You probably know many of these filters under names such as Eheim, PEP, Lifeguard, Magnum, Fluval, Atlantis, Tech, and assume that they all fall in the same category. That is not the case. Some are meant to be strictly mechanical filters, others can be adapted to perform several distinct functions: mechanical, chemical, biological, even heating, or a combination of several of those. The latter is what we would like to strongly discourage. Segregate, don't combine. Keep all forms of filtration separate from each other. We must also differentiate between the traditional canister filters such as the Eheim, Fluval and Magnum types, and the others mentioned. The former can be loaded, or filled, with varying types of products, each one of which is meant to perform a different function. The latter are more of a pressure type filter, excellent at mechanical filtration. In fish-only tanks that was certainly a very appropriate way of using these filters; in Reef tanks, we would like to discourage you from doing so (combining several filtration methods). Remember, we are trying to keep all forms of filtration separate from each other, and since we will be using a trickle filter (see biological filtration), if you use a traditional canister, you should use it as either a mechanical or a chemical filter, not a combination. Let's review how to use them as mechanical filters. Refer to the last section in this chapter to check up on chemical filtration canisters. Canister filters have one great advantage : they can easily be opened and serviced. That is a boon ! The easier it is to clean a filter, the more often the Hobbyist is likely to do so. And cleaning the inside of mechanical filters often is a requirement, not an option, as we have already seen. Fill your canister with any material that is available in your local area pet store, and that is meant to be used in a fine filter. Pack it in firmly, but not too tightly, lest you will restrict the water flow too much. Canister filters can move a fair amount of water, but their pumps do not usually take a lot of back pressure. Switch the canister on, and you will be mechanically filtering the water on a continuous basis. You can take water from the bottom of the trickle filter (sump), and return it to the same area, or you can return it to the tank directly, or to the top of the trickle filter. All three are acceptable. In-line mechanical filters are discussed later. Many Hobbyists use filter floss, some use ceramic tubes such as EfiMech from Eheim (stands for efficient mechanical filtration), kordon's equivalent : BioMech, pads such as blue-white bonded ones, coarse gravel, DLS or copy-cats of the original, foam sponges (beware though that most foam is bio-degradable, and if it is not, it may have been treated with compounds you do not want in your tank), natural sponges (my favorite), crushed coral, small coral rubble, Efigross (grob) a fine mesh of green plastic marketed by Eheim, layers of untreated viscose, and a host of other materials (hobbyists are very resourceful in this respect). Clean the filter(s) at least once a week, more often is even better. Do not worry about bacterial loss, mechanical filters are not meant to act biologically. That is not their purpose. In fact, more often than not, the bacteria that grow in mechanical filters that are not regularly cleaned, do more harm than good, and some even suggest (de Graaf, 1976) that they may be the cause of wipe-outs, in some cases (Shigella type bacteria). Cleaning the canister, cum mechanical filters, involves removing all the material that you placed inside, and rinsing it thoroughly in fresh water before placing it back in the canister. Sometimes it even pays to use new material, e.g. in the case of filter floss. Some materials need to be scrubbed, others bleached. In the latter case make sure you rinse them several times to remove all bleach leftovers. Do not, if you can avoid it, use dechlorinators. I do not care for their use in Reef tanks. In order to make this process as easy as possible, it is suggested that you use quick disconnect shut-off valves, on either side of the canister filter. This will allow you to take it out of service without having to worry about water spillage, except for the very little water that is between the canister and the quick disconnect valves. Eheim, Fluval and Marineland make such valves, and there may be others. American made ones are as good as the imports, so my suggestion is that you save yourself the extra cost, as imported ones are usually more expensive, and not necessarily better. The size of the canister should be in direct relation to the size of the system that you have. In most cases a Fluval 303, or perhaps a 403 for 55 gallon aquariums will be fine. This may be larger than what you expected, but you will benefit from the extra mechanical filtration ability that you will have. There are of course other brands; get the larger models if you can afford them, they will do a better job for you, as they hold more filtering material. Eheim, probably the inventor of the canister filter, has recently introduced its 2200 series, very similar to the previous 2000 series, but with slightly more flow, and a normalized shaft. These top-of-the-line canisters are really good value for your money and hold up for years and years. I personally use Eheim 2217Us whenever I need canister filters. Filter floss is, in my opinion, just about as good as anything else you can find on the market. It is easy to use, relatively inexpensive, and can therefore be replaced each time you clean the filters. Buy it in bulk. Make a habit of cleaning your canister(s) at least once a week. Your system will greatly benefit from it. That is my experience anyway. And if, as suggested, you use quick disconnect valves, cleaning and changing will not be a chore at all. Remember, the easier it is to clean your mechanical filter, the more often your are likely to do so, for the benefit of your system. I have said so for a very long time, and must remind you, that only when you first set up your tank, can you meaningfully influence this. Install all mechanical filters in a way that will let you reach them easily. CANISTER FILTERS (special) Special canisters can be acquired to mechanically filter the water. Two examples are the PEP and Lifeguard Systems. These units usually require some piping, unlike the traditional canisters which the Hobbyist can just plug them in and run. Their installation is, however, not complicated, and if you already have them, by all means use them. Most of these filters (there are others besides the two mentioned) use some form of pleated bag, or pleated device, to increase the amount of surface area through which the water can flow and be filtered. The more surface area, the better the filtration, of course. The bags can be used as such, or special powders (often diatomaceous earth) can be added to the filter, to step the filtration up to very fine levels, in this case referred to a micronic. Cleaning is a little more involved, as these bags usually need to be bleached to remove the accumulated detritus. This takes more time and requires that you make sure all the bleach is removed, before putting the bags, or other material, back in the canisters. It is, actually, a good idea to have an extra bag or pleated cartridge around. Especially so if your local pet shop does not normally carry them. Because of the way they need to be cleaned, the pleated bags or cartridges will wear out. Make sure that whomever you buy such a unit from, if you decide to include this in your filtering system, will also be able to supply you with replacements. Some dealers don't, or you may have to special order them. Although this type of filtration can be very efficient, it is, in my opinion, not a necessary expense on the smaller Reef Tank. However, if you have such a filter already, it is recommended that you use it anyway. They are indeed very efficient at removing even very fine particulate matter. Some units come with pressure gauges. This allows you to determine when it is necessary to clean the cartridge (pleated bag or other device) based on what the manufacturer suggests. Indeed, increased levels of pressure inside the canister are an indication that it is plugged, and needs cleaning. Retro-fitting such pressure gauges is also possible. If you plan to use one of these units, make sure that the pump that you will be using can handle the back pressure brought about by these filters. Small pumps will not do the job. Again, most manufacturers suggest which pump you should use. Because canister filters are very versatile, some brands are offered in various configurations, e.g. heater modules, chemical modules, and of course, mechanical modules. Lifeguard and PEP are two examples. Unless you already have one of them, we recommend an alternative way of fine filtration; less expensive than acquiring such units. Use either a canister, or check the section on trickle filters to see how fine filtering can be incorporated in the trickle filter itself. In fact, ideally, this option should be provided in the trickle filter you should get, either as an easy add-on option, or already built-in. Special canisters, such as the ones described, come in various sizes, and if you plan on getting one, match the size up with what is recommended for your tank. Better still, buy one size larger. It can't hurt the system, and if you up-grade to a larger tank, you will probably already have the right size canister, and save yourself the extra expense of having to buy a new one. You may not be thinking about a larger tank right now, but believe me you will at some point. Most Hobbyists do. Servicing will require that you shut your pump down, as these filters are usually piped in-line with the main water flow back to the tank. In fact, some tanks' filtration consists only of a series of these special canisters. Such may be efficient, but in a Reef set-up we do not recommend that you use such filtration as the only means of maintaining water quality. They can, as we have seen, be used as add-ons to the trickle filter, especially for mechanical and chemical filtration. Shut-off valves should be placed on either side of these units, to allow for quick and easy opening and servicing. True union ball valves are probably the easiest type to use. Quick-disconnect shut-off valves are another possibility, and for most Hobbyists a less expensive way to go. Piping in a by-pass line may be a worthwhile option, as it will allow you to service the filter without having to stop your system. To check how this is done, look at the drawing, a few pages ahead, in the section on molecular absorption filters and micron filters. These type of special canister filters are often used in swimming pool and similar installations (e.g. spas). When shopping around for one, check your local pool places too. You may be able to get yourself a bargain. If you need fittings and plastic pipe, check the hardware stores, the do-it-yourself stores, and best of all, the local plumbing supply places. If you run out of options, U.S. Plastics, also called Industrial Plastics, in Lima, Ohio, sells by mail and has excellent prices. DIATOMACEOUS EARTH FILTERS Diatomaceous earth, the skeletons of diatoms, allows extremely fine filtering, usually down to 1 micron, a level at which many parasites are trapped as well. This is very efficient filtering, but should, in my opinion, not be used too regularly on a Reef Tank, as it will filter out all of the free floating lifeforms that many filter feeders in your tank require for survival. Tanks always contain filter feeders, and depriving them of the food they require is not a sensible way to run such an aquarium. If you use a Vortex Diatom, a Marineland, or a System 1 diatom filter, do so infrequently, and not for many many hours in a row. Use them to clean the water after you stir up the bottom, to remove particulate matter that is now floating around, and then clean the filter and put it away for a while. Regular use is, in my opinion not recommended. Of course, in fish-only tanks they can be run continuously. Suggestions have also been made that the use of diatomaceous earth may add silicates to the water (Thiel 1986, 1988). That is undesirable insomuch as it may result in the appearance of live diatoms, which will make the tank look really unsightly. To demonstrate this fact, run water through a diatomaceous earth filter for a few hours, and test for silicate both before and after. You will be up for some real surprises. Some of these filters can be used with powdered activated carbon as well. This is something to consider doing on an infrequent basis : once every 2 weeks, to once a month perhaps, to clean up the water chemically as well. Never use the diatom powder more than once. Clean the filter after each use and throw the powder away. If you let it sit in the filter, it will cake up, and anaerobic bacteria will appear within hours. When you then switch the unit back on, all the noxious compounds in the filter will enter your tank. A most dangerous situation that can lead to many problems, including massive die-offs ! Should you get such a filter for your Small Reef ? My own answer is no. The drawbacks are the filtering out of fine matter that filter filters need, and the possibility that silicates are added to the water and may give rise to live diatoms (for example Navicula, Berkeleya). If you happen to have one, use it very infrequently, and use the types that does not require diatomaceous earth. There are better ways of fine filtering the water that are more efficient. SAND AND GRAVEL FILTERS Perhaps the best and certainly the least expensive to set up. A small old aquarium will do (if you don't have one, look in your local bargain newspaper in the pet section, you will find them advertised all the time). The filter can be set up using a regular canister filter as well, filled with gravel (or sand, although it is probably better to use gravel. Because sand is finer than gravel, sand filters will filter much finer material out of the water, but not as fine as to remove what your filter feeders need. Gravel is probably good enough and is easier to maintain and clean. Additionally it is unlikely that anaerobics will start in your gravel filter if you clean it regularly, and if water flows through it continuously. You can use traditional canisters or special canisters, or you can build one yourself, using a acrylic tube that is outfitted with a top and a bottom. Since you will need to be able to access the inside to clean the filter, you must use some device that allows you to do so. A compression nut is usually best. Make sure it is all plastic, or if any metal is in contact with the salt water, it must be 316 SS. If it is not, you should coat it with some plastic liquid paint, or with aquarium silicone. It is placed in the top or bottom of the cylinder and tightened. When the gravel (or sand) needs changing or cleaning, the cylinder can easily be opened, the filter material taken out, cleaned and placed back in the cylinder. Although this type of filter may not be in wide use, it is one of the most efficient and also very inexpensive to construct or set-up. Remember to clean it regularly. You must remove the dirt that you have trapped from the system (the total mass of water in the aquarium and what is in the sump of the filter, pipes, hose, etc.). If you are not handy, or if you do not want to make the cylinder yourself, some can be obtained commercially. Alternatively, use the aquarium with divider method, shown in the diagram. MICRON AND SUB-MICRON FILTERS Similar in their effect to the diatomaceous earth filters, micron and sub-micron filters are extremely efficient at cleaning up the water mechanically. They will remove even the smallest matter, especially if one uses the sub-micron (smaller than 1 micron) variety. They often consist of a canister outfitted with a cartridge, or bag(s), that will not let particles through greater than the size the bag, or cartridge, is rated for, e.g. 5 microns, 1 micron, 0.65 micron etc... (see also diatomaceous earth filters which perform a similar type of filtration but use a different compound, and the reservations about using such filters expressed). At that level of filtration even parasites are filtered out. Unfortunately so are all organisms and matter that your filter feeders feed on, and need. As already indicated this is not desirable. If you plan to use such a filter, use it only intermittently and not for extended periods of time. It is important to keep in mind also that such filters put a great deal of back pressure on the pump(s) and that you will lose more and more water flow, as the bag or cartridge loads itself with detritus. Filters of this kind are rated in both nominal and absolute ratings. Nominal simply means that they will effectively remove most of the matter larger than what the filter is rated for, e.g. 90 percent or better. Absolute means that they remove all matter larger than the rating. As you can well imagine the second variety is quite a bit more expensive than the first. Several standard canister filters can be outfitted with special inserts that act as micron filters. This usually does not make it necessary for most Hobbyists to buy a special unit. The better ones, however, are filters specifically built for the purpose of micronic filtration. One such example is the Poly-Bio-Marine PSM-1 filter, which can easily be installed in line, and used in conjunction with the PMA-1 filter, the molecular absorption type (see Chemical filtration for more explanations on that type of filtration). If you install a micron or sub-micron filter in-line, you should pipe it in such a way, that it can be by-passed, by switching valves. This will allow you to run the system without the micron (sub) filters for most of the time, and run the filters only when you want to, for short periods of time. By leaving the valves that control the in and out to the fine filters slightly open, you will allow some water to go through all the time. This will prevent the formation of anaerobic activity in those canisters. It is even used by some to function as a denitrating filter. When doing so, you must make the water flow through the canister/filter, very slowly. Since you will also have to be able to clean the filter, you will need a total of three valves to perform this. The illustration clearly shows how to pipe such a system, either with hard pvc pipe, or with acrylic or flexible pvc hose (better). If you are not sure how to do so, check with someone who does, or call somone in the Hobby you know who can explain to you how to set such a system up. These filters put a great deal of strain and back pressure on the pump(s) you are using. It is, therefore, a good idea to plan for a pump that can handle that pressure, when setting up the system. These filters only make sense in a small Reef aquarium if you happen to have one already. I do not recommend it as a integral part of a basic set-up. Save yourself the expense. And if you do decide to buy one, get a good quality unit. The PSM is probably the best you can get and the easiest to service. MISCELLANEOUS Mechanical filters can be made using any convenient container and filter floss or gravel, or a combination of both. This is easy to achieve if you are using a trickle filter at the same time, as all you will need to do is first flow the water into that container, and through the media, and then from that container to the top of the trickle filter. A old aquarium, or a plastic bucket if that is all you have, will do just fine, and will make the filter quite inexpensive. In fact, if you refer to some old FAMA magazines, in the For What it's Worth column, you will find many suggestions on how to set such filters up. Without a trickle filter (see biological filtration) it is very difficult to use this form of mechanical filter, unless float switches (level switches) are used as well. This complicates the set-up and can increase its price quite a bit. One tried method that is often inexpensive to install, consists of using old canister filters, place them in series, and run them with an old pump you have sitting around. Not the pumps that came with the canisters, but something stronger than that as, to push water forcefully through one or more canister filters, you may need something the equivalent of a Number 2 or 3 magnetic drive pump (brands include Little Giant, March, Iwaki, and others). Do not use extra strong pumps as the canisters will not take a very high amount of inside pressure. If you do not own such a pump, look in your local bargains advertisement paper, ask the Pet stores you deal with for second hand pumps, or call other Pet Stores in your area. Your local Aquarium Society may also be a good source for getting equipment you need. MECHANICAL FILTER IN SYPHON : To bring water down to a trickle filter two methods are used. Either the surface skimming syphon arrangement, or holes in the tank combined with a corner overflow box (see The Marine Fish and Invert Reef Aquarium for a detailed discussion). A number of syphon devices have a pre-filter (mechanical filter) built in to the downflow. That is of course an excellent way of filtering the water, as it is done one step before the water enters the biological part of the trickle filter, thus reducing the amount of detritus that can get stuck there. This is especially important with certain types of materials used in such filters, e.g. DLS and similar materials that go by different names. The latter, due to its denseness, can indeed trap dirt very easily. Such is totally undesirable, as it will quickly lead to reduced levels of dissolved oxygen, which, as we shall see later, will stress all tank life, and lead to a system that is not running at its optimum, and in which disease and micro-algae will more than likely occur intermittently or, more likely, all the time. Mechanical filters inside syphons are usually made of coarse foam that traps the dirt. Clean it regualarly. At least once a week. Remove the sleeve, or twist it loose (as in the Smit's Natural Reef model and also in a few others), rinse it out, and place it back in the syphon. CONCLUSION : You must clean the water with a mechanical filter, and you should do so before the water enters the biological filter. You must clean the mechanical filter(s) regularly, at least once a week. More often can not hurt, to the contrary. You should, in my opinion, not use micronic, sub-micronic and diatomaceous earth filters on small Reef tanks, and if you do, you should only use them very infrequently. The denser the material inside your biological filter contact chamber, the more importance mechanical filtration of the water going to that filter, before it gets there, becomes. Indeed, this will prevent dirt getting trapped too quickly, loss of dissolved oxygen and decay inside the biological filter. Several mechanical filters, instead of just one, do not hurt the system, on the contrary, but are, in my opinion not a requirement. They just add to the cost of setting up the tank, unless of course you have them standing around anyway. A complete trickle filter with all the required types of filtration incorporated, and segregated, is the ideal system to go with for a small Reef Aquarium. How such a filter is built and what it looks like may not be what you have in mind right now. The traditional box-like filters that have been around for several years are obviously one way to go, but there are other approaches that we will discuss. Look for our recommendations on mechanical filtration later in this book. You may also wish to refer to the How To section of FAMA magazines, as many ways of fine filtering have been described there. Incidentally, FAMA published all the HOW TO's in book form. Check with them for ordering information. FAMA is the abbreviation for Freshwater and Marine AQUARIUM magazine. [Albert J. Thiel requests that you make a $5.00 donation to the New Mexico School for the Visually Handicapped Children, 1900 North White Sands, Alamagordo, New Mexico 88310 (or other charitable group) if you download the entire book. This would be in lieu of the standard purchase price for this publication.] SMALL REEF AQUARIUM BASICS BIOLOGICAL FILTRATION General Remarks What biological filtration is all about, is not the subject matter of this book. You may wish to refer to general marine aquarium books if you are not entirely familiar with biological filtration, or if you want to read up on it some more. One not-general-at-all book, but a very detailed one on marine aquarium systems that we highly recommend is _The Marine Aquarium Reference-Systems and Invertebrates_, by Martin Moe, 1989. It contains a wealth of information that you will be interested in, as well as many practical tips and advice that you will be able to put to good use. Besides that, it explains a lot of the more theoretical concepts in clear language, understandable by the average Hobbyist. Biological filtration is a very important component of your total filtration system. As most of you know, breakdown products of metabolism and decay of protein, produce either ammonium ion or ammonia depending on the pH of the medium . In a marine environment where the pH is relatively high, a percentage of this ammonium ion is in the form of ammonia, a very soluble and toxic gas. Even very small amounts of NH3 are extremely toxic and will cause great stress to the fish and invertebrates, killing some of them off, which creates more pollution and more stress. To remove this ammonia and ammonium ion nature, comes to our help with the nitrification process, whereby ammonia is converted to nitrite, and nitrite to nitrate by bacteria that will grow spontaneously in the tank, or that can be added (seeding) when first starting up the tank, to speed up their proliferation. Bacteria grow everywhere, not just in a biological filter. Please keep that in mind. The size of the bacterial population is also determined by the amount of nutrient available to them. Keep that in mind too. Most Hobbyists do not, and think that once their filter is cycled, they can put a large number of fish and invertebrates in the tank, without danger, and immediately. That is not so ! It is a mistake very often made, and it leads to die-offs, disease, stress, and a host of problems. Look at it this way : a biological filter that is very potent during the cycle, can only keep sustaining the same amount of pollution as it had during the cycle. If you increase the load in the tank to beyond that level, the filter has to readjust and build up even more bacteria. To simplify the explanation : if you had 5 pieces of so-called live rock in the tank during the first 4 weeks (i.e.during the cycle), and it required, for argument's sake, 7 million bacteria to cope with the pollution so generated, you cannot expect those same 7 million bacteria to cope with 10 pieces of live rock (keep in mind that the numbers are arbitrary and bear no relationship to the real numbers. They are only used to illustrate a point). To cope with this new load you will need even more bacteria. They will grow spontaneously in your filter, but it will take a few days for them to appear and neutralize the increased amount of ammonia (and subsequently the higher amount of nitrite). Each time you add an animal or an invertebrate, more ammonia is generated and more bacteria are necessary in the filter to neutralize that pollution. That is the reason for the often found recommendation : add new tank inhabitants only a few at a time, and wait several days between each introduction ( your safest bet is to check for ammonia and nitrite, if none is found you can add more lifeforms). Indeed, doing so let's the filter catch up (meaning more bacteria grow) without creating undue stress on the animal life already in the tank. This results in a safe and gradual increase in the tank's population. If, in addition, you use the recommended methods for adding fish and inverts, you should not have any problems with outbreaks of parasitic infestations. No one can offers 100 percent guarantees, but if you follow these recommendations, your chances of not getting any parasites will be greatly improved. You are, then, also less likely to lose the animals (and the money they cost you). Marine Reef, the newsletter, featured several articles on this subject already. A similar remark applies to biological filters that are started up with several rocks or fish, and then left to run with far less lifeforms for a while. The filter adjusts to the lower amount of pollution. If the Hobbyist then decides to place a larger number of lifeforms in the tank again, the filter will not be able to cope with this increased load. It will need to readjust first, and that takes time. If you do not let the filter adjust, stress will be created and lifeforms will be lost (or as often is the case, disease will break out). This is an important remark to remember with regard to biological filters ! How long the readjustment phase will take cannot be predicted. Testing for ammonia and nitrite is the only sure way to deter-mine whether or not the filter is ready for an increased load. Both should test zero ppm (or mg/l). We noted that mechanical filtration is important for two reasons : it removes particulate matter before it can break down and pollute the water, it makes the tank look more appealing, by unclouding the water and removing debris. Correct biological filtration is very important because it : breaks down ammonia to nitrite (Nitrosomonas bacteria) breaks down nitrite to nitrate (Nitrobacter bacteria) oxygenates the water for the benefit of all lifeforms and the filter itself. removes a number of unwanted compounds through facultative aerobic-anaerobic activity in portions of the filter (Wolff 1984). Incidentally, and as a reminder that trickle filters are not some recent development, the first reference to such filters that I could find is in a book published in 1935, yes that long ago, called American Sewerage Practice, by Leonard Metcalf and Harrisson Eddy, Volume 3 of 3, The Maple Press Company, York, Penna. Call them if you are interested in how large volumes of water get treated. That book was brought to my attention by Matthew Cammarata. The filters in that book are large, some even very large, at least compared to what we use in the Hobby nowadays, but the principle behind their efficiency has not changed an iota over the years. Such biological filters (not necessarily all trickle filters) can be set up in many ways. All work of course, or Hobbyists would not have used them for several years now, and they would not be around in the literature anymore. There are however varying degrees of efficiency in the types, brands and models available on the market. Some just do a better job than others. You know most of them : Canister filters, traditional Canister filters, special Undergravel filters, regular flow, reverse flow Outside box filters Trickle filters in many configurations and a combination of one or more of the above. There are other types of biological filters too, perhaps not as familiar to you, but they are used by a fair number of Hobbyists too: BioMesh filters Ruecksack or Backpack filters (hang-on trickle filters) Tray Filters, similar to trickle filters Outside the tank biological sand filters and a variety of intermediate ones, based on the sand filter system. All of them serve the same purpose : the three reasons stated above. As indicated, however, some of these filters do a much better job than others at improving water quality, especially where it comes to re-oxygenating the tank's water. For years in the hobby, especially in Europe, the trickle filter has made great strides in this country too. In 1985, when I first imported trickle filters from Germany (from a company called Nollman Aquaristik, in Sennestadt), hardly anybody even knew what such filters looked like, or what they were supposed to do. Nowadays, just looking at the ads in the Hobby magazines, everyone seems to claim "they" were the first to ever offer this type of filter (refer too to my earlier remark about the 1935 reference to trickle filters in _American Sewerage Practice_ to convince yourself that such is merely advertising copy). Who was the first, and when, is not important and germane, what counts is that these filters are extremely efficient, and that for the purpose we are interested in - high quality water - they are the foremost filter, and the most effective at the present time. The variety and number of such filters now available attests to their success, and to the fact that both manufacturers, and Hobbyists alike, believe in them. Because I strongly believe that to run a successful Reef you need such a filter, or a similar type e.g. a hang-on unit (Ruecksack or some types of conversion units, for instance), we will review only such filters in this section. Information on undergravel, and similar filters, can be found in many other books, as I am sure you are aware of. Refer to them if you still want more details, or if you want to review and compare them with trickle filtration. Inside an appropriate compartment, a medium is placed on which Nitrosomonas and Nitrobacter can grow in large numbers. The shape of the box has absolutely no bearing whatsoever on the efficiency of the filter, although most manufacturers make them square or rectangular, because round tube or pipe of the size usually required, would make the filter much more expensive. When dealing with the shape of a trickle filter, the important factors to take into account are the following, in my opinion: filters that are too narrow tend to create "channeling" of the water against the outside panels of the filter, resulting in very inefficient use of the medium, filters that are short, meaning not tall enough, do not promote re-oxygenation very well, and are therefore not as desirable. The minimum suggested height of the column of biological medium is 12 to 14 inches. Most filters you see are clear, probably because clear acrylic is less expensive than other varieties. In fact, the filter would do better if it was not clear, as the bacteria perform better in the dark (documented in too many articles to mention). Nollman Aquaristik, of Sennestadt Germany, which has been building filters for many more years than anyone in the USA, builds theirs in opaque PVC sheet. Luebbecke Aquarium who have used large trickle filters on their 10.000+ gallon system for many years, uses 3 foot diameter grey PVC pipeline sections. Another reason may be that clear filters can easily be looked into, something the Hobbyist likes to do, to determine how the water is flowing through the medium. The biological filter compartment should be removable from the other parts of the filter. This allows for easier transport and shipping, easier installation, and much easier cleaning of the other parts of the filter when the need arises (and it will, believe me, mainly because most filters on the market do not have slanted bottoms which will require you to syphon out detritus from time to time). As the water comes down from the tank to the filter, and disperses inside the biological chamber, it travels over the medium and allows the bacteria that grow on them to polish the water by first converting ammonia to nitrite (one type of bacterium) and then from nitrite to nitrate (another bacterium). The better the dispersion of the water, the better the water is spread over the medium, and the better the filter will be able to clean up the water. That should be obvious. Not only is filtration more efficient, but by using the medium more efficiently you will need less of it. This can save you quite a few dollars as most of the media are still relatively expensive. Additionally, less medium fits in a smaller filter, and that too will save you money. It will also make more space available underneath the aquarium, and since space there is at a premium.... Because you do not want to have to clean the biological filter - in doing so you would destroy a large amount of bacteria - the medium should allow a good throughflow of water, and not trap dirt that may have slipped through your fine filters (mechanical filtration). It isn't supposed to, but some will. If it gets stuck in the medium, in the long run you are looking at cleaning it. We already stated that such is not desirable at all. Dense material will plug up no matter how well you filter. The main reasons for this is that fine particulate matter not trapped in the fine filters will eventually clog certain areas of your dense biological filter, creating anoxic pockets. When oxygen levels are low, or non-existent, decay is proceeding anaerobically, and hydrogen sulfide is produced. This will pull your water quality down very quickly. In fact, if you were measuring redox potential levels, and they are low, even though you are using a considerable amount of ozone, the likely reason is that small amounts of hydrogen sulfide are pulling the redox down, because of the reductive power of hydrogen sulfide. Increasing the ozone may not even help. You must eliminate the H2S to bring the redox potential back up. There exist of course many other reasons for low redox potential, some of them will be covered elsewhere in this book, especially in the Maintenance Section. Components of a Good Trickle Filter : We already mentioned the biological compartment. Several features of this compartment are important, because they add to the efficiency on one hand, and to the ease of installation and servicing on the other : Because acrylic warps easily when in contact with water, good reinforcements of the side of the biological compartment are very desirable. Beware of filters made out of very thin acrylic or similar materials. They will warp, and may split on you, unless reinforcements have been added to prevent this from happening. A removable lid is a plus. Dirt will get into the top of the filter whether you like it or not. When the lid at the top is removable, it will be very easy for you to remove that dirt. The lid should also be reinforced, or made out of glass (best). If you can't get to the top, the dirt will do two things : it will decay and reduce water quality, and it will plug up holes in the drip plate (if that is what you are using, and you should). At least two air inlets are recommended. The bacteria inside the filter are aerobic, meaning that they require oxygen to perform. Blowing a good flow of air into the filter is therefore very desirable. The better the air is spread out, the better the filter will operate. I usually recommend that Hobbyists use a air pump such as a Whisper 1000, or stronger (e.g. Wisa), and blow all the air inside the biological chamber, using both the air inlets. If only one is available, you may wish to drill a second one, push airline tubing through it, and then pack a little aquarium silicone around the hole, so no water comes out. Blowing more air will not hurt, to the contrary. To convince yourself of the benefit of doing this, run air into the biological chamber, note the redox potential, now shut off the air, and then watch what happens to the redox potential: it will go down (Bepko, 1988, Thiel, 1988). It may even go down quite a bit. You must blow the air into the chamber above the water level, directly into the column, not through an airstone placed in the water underneath the biological chamber. The height of the chamber should be at least 12 to 14 inches. Shallower filters will work, but you will need to flow more water through them. Because there really is a limit to how much water can be flowed through a small biological chamber. Excessive current through the filter will wash off some of the bacteria, and result in a less efficient filter, less oxygenation, and a smaller biological colony. The width of the chamber should be no less than 8 inches. Narrower filter chambers channel too much water on the sides rather than through and over the medium used, and that reduces the efficiency of the filter. Use a filter with a drip plate rather than a spray bar. The reasons for this are explained in the section on drip plates, later in this section. The chamber should not sit too deeply in the sump. This will keep all the medium out of the water in the sump. Bacterial beds that are out of the water are more efficient at handling ammonia and nitrite. Wolff (1984) suggests that the efficiency goes down to less than 60 percent when the medium is submersed. Larger sumps are to be preferred. They increase the total volume of water in the the system, and make it easier for you to use a powerful pump. If too little water is in the sump, evaporation will lower its level quickly, and if, as you should, you are using a float switch, the pump will stop regularly, and eventually altogether when the water level is real low. Larger sumps also have more space for other devices that you may want to add to your system and that you may wish to run with a power head. The sump should preferably be reinforced too, as this will prevent warping and possibly splitting months down the road. Compartments built in the sump are always a plus. They allow you to easily add certain compounds to the system. Make sure however that the compartments are built in such a way that the water coming from the biological chamber must flow through them, not just over them. Whatever you place in them will work better if the water has to go through the compound completely. Depending on the size of the tank, you will be using a particular pump. Check the in and outlet sizes of the pump. Make sure the hole in the filter is of the same size, or larger, than the size of the pump intake. Re-drilling an existing hole is not the easiest and safest thing to do. If a bulkhead fitting is already included you will not have to go out an buy one. If you do, buy a real tank fitting, not a rigged male/female fitting type arrangement. Built-in foam fractionators - protein skimmers - are a definite plus, but they must be of the size that your system requires. Not some flimsy little skimmer that was built to fit the filter rather than the tank! This is most important because undersized skimmers will be a real problem for the tank, and are one of many reasons for the appearance of red algae. See the section on skimmers for more details on sizing. Don't lull yourself into thinking that you have one if the filter you bought has a real small skimmer built into it. Stick with either an outside columnar one, or a built-in Venturi skimmer, and make sure that you can use ozone with it, because you probably will want to, or need to. A sump with a slanted bottom will allow mulm and other detritus from being moved forward by the current, making it much easier for you to syphon it out. Mind you, mulm is technically speaking inert, and should not affect the water quality any longer, it is the detritus that needs to be removed. Certain filters have a built-in tray for electrodes. That is handy if you are using them, but in the basic system that we are setting up, we will not. Whether the sump has a lid, or not, does not really make much of a difference. Most of the evaporation is not from the sump, but from the aquarium itself. It makes the filter look more finished though. Sizing the Trickle Filter : From an economics standpoint this is a most important section. Buy a filter that is too large and you spend more money on the filter and also on the internal medium. Buy one that is too small, and your water quality will suffer, and you may lose fish, invertebrates, and ultimately money too. In my estimation, buying the wrong filter will end up costing you two to three hundred dollars more than you should have spent. Of course, building your own filter would be the least expensive way to go. Plans are available in the magazines, and were also published in my other books. The ultimate size of the filter will largely depend on the internals (biological medium) you use. The better the medium, the less of it you will need, and the smaller the filter will become as a result. Here are my suggestions for sizing, providing you use either Bio-Techs, or Bio Blocks. Both are available from dealers nationwide, and cost about the same per gallon volume of the material. Tanks up to 40 gallons : you will need 4 gallons of internals. Tanks up to 55 gallons : use any trickle filter that can hold 4.5 gallons of the above materials. Tanks up to 70 gallons : you will need a filter that can hold 6 gallons of biological filtering medium. Tanks up to 110 gallons : 7.5 gallons of capacity required. Tanks 125 - 135 gallons : 8.5 gallons of internals needed. Tanks 150 gallons : 10 gallons . The above numbers are lower than what you normally will find recommended because they are based on tests, not on advertising claims made by various manufacturers of plastic filtering media. They assume you follow the directions in this book : most importantly that good dispersion is achieved by means of a "drip plate" of the kind we describe. This means that you may have to slightly modify (easy and explained later) the drip plate that comes with the filter you have bought, or are using now. Why are these recommendations lower ? Over the last 5 years I have had the opportunity to personally use the following media: German blue balls, Jaeger Tri-Packs (2 sizes), Bio Cubes, Bio-Techs, Pall Rings, Norton Rings, Plastic haircurlers, EfigroB, Raschig rings, Bio Discs, Cut PVC pipe, Cut acrylic chips, Gravel trays, Sand trays, Beads, Dolomite, and others still. Doing so gives one a pretty good experience with which materials provide the kind of filtration required for Marine Reef tanks, and allows for fair and educated comparisons of their respective merits. The following criteria guided me in deciding which internal plastic medium to use myself, and recommend to others : Dissolved oxygen levels after all ammonia and nitrite was converted. Speed at which ammonia was converted to nitrite and, Speed at which nitrite was converted to nitrate, Gaseous exchanges : e.g. was the CO2 level within the norm? Do they trap dirt, how much, and what size ? Once dirt is trapped, how long does it stay in the filter ? Does water flow evenly, continuously, over the medium ? Does channeling occur, and if so, do what degree ? Does the material you are using stack up ? We have not recommended a product called pax, because it seems to trap more detritus than we feel is safe for your system. Unless some modifications to that material are made we feel that it is not a "best buy" for Reef tanks. It does well for fish-only tanks however. Biological filtration in Reef Tanks requires attention to details, not just "surface area" or "dispersion ability." Select what you buy very carefully. Important Media Considerations : The following qualities are important considerations when buying internal plastic biological filtration materials (usually Polyethylene, or plastic, as it is generally referred to) : the material should not trap dirt and debris. This includes pieces of food, algae, and any other free floating particulate matter. the material should allow good gaseous exchange by braking up the water in really fine streams and drops. the material should have a relatively large surface area. You will need somewhere between 2 and 2.5 square feet of biological filtration area per gallon of water in the tank. The exact amount, whether the lower number or not, depends on the load in the tank. If the distribution of the water over the medium is really maximized, you can go as low as 1.25 square feet of surface area per gallon of water. the material should be totally inert. No leachings whatsoever are allowed. the material should maximize the utilization of the biological chamber. This means that there should not be large gaps between the individual media pieces. the material should be permanent, meaning that it does not deteriorate, and thus never needs replacing. the material should be unbreakable, so that no rods, or pieces, break off and ruin the pump impellers and volute, and possibly the inside of a chiller, if you were to use one (not part of a basic system of course). it should not be too rough as that would result in dead bacteria being overgrown by live colonies, which is not desirable as it will lead to very small amounts of anaerobic activity underneath the live active layer, possibly killing some of the live layer of bacteria off, or reducing its potency due to anaerobic activity by-products (Thiel, 1988). Drip Plate or Spray Bar ? The controversy surrounding this topic has been going on for quite some time now. Very simply, it is my educated opinion, based on extensive testing, that drip plates perform better in trickle filters than spray bars do, because : they distribute the water more evenly, contain dissolved gasses better, and are not subject to clogging , and slowing down, the way spray bars are. We, therefore, now recommend drip plates in trickle filters, and have, after trying many variations, arrived at the drip plate that we feel performs best : Hole size of 3/16" Holes separated by 3/4 inch spaces, Plate grooved for better water distribution, Hole size commensurate with flow rate, Holes tapered at the top of the place. No holes within 1 inch of all filter sides, to reduce channeling You can modify an existing drip plate by plugging holes that are too close to the sides with aquarium silicone, and add holes if necessary. If the plate can be removed you can do so rather easily, if not, you must drill the plexiglass plate while leaving it where it is. Use only acrylic drill bits! They will prevent cracking of the acrylic when you drill through it. They are not expensive, and are sold at most stores that sell acrylic in custom cut sizes. To position the holes correctly, draw lines with an acrylic scratching tool, 3/4" apart length wise, and 3/4" apart cross wise. Then drill holes where the lines cross (see drawing below). To obtain tapered holes, use a small countersink drill bit after you have drilled the holes. This gives the tapered effect which will improve the flow of the water downwards into the biological chamber, and over distribute it better over the medium you are using. Although the drip plate may not appear to you as a significant part of the trickle filter, it is a very important one. Indeed, by selecting the correct one, or modifying it as we suggested, you can ensure a much more even dispersion of the water coming down from the tank, over the medium that you are using. That in itself assures a more efficient biological filtration and, ultimately, a greatly improved water quality, the purpose of using a trickle filter to begin with. Retrofitting for a slanted bottom : Most units on the market have a "flat" trickle filter bottom. As we have seen, this does not promote the forward moving of detritus and debris. Retrofitting an existing filter is not complicated at all : Measure the inside dimensions of the sump very carefully. The match of the plate you will be adding, with the inside of the sump must be exact. Measure from the back of the filter, coming towards the front, up to where the biological chamber ends. The plate only needs to be long enough to fit underneath the biological chamber. Acquire the piece of acrylic from a plastic dealer in your area. Place the plate in the sump in such a way that it slants forward at an angle of a few degrees only. Dry the sides where you will need to glue properly. This is really important because glue does not stick if the sides are still moist. Go over the sides of the filter with paper towels several times. Use aquarium silicone to glue the plate in place. Glue with care because you need a very good seal. No water can be allowed to get underneath the plate. It would stagnate and create anaerobic conditions. Let dry for at least 75 minutes, preferably somewhat longer. Since not a great deal of pressure will be exerted on the seams you glued, you will not need a 24 hours curing period. The force of the current over the slanted plate will now move the debris and detritus forward, and you will be able to syphon it out very easily. In the process you will prevent it from decaying in the system and reduce your dissolved oxygen levels. Adding Compartments to the Sump : Rather than buying canister filters to add certain water filtering products to your tank, you may wish to add compartments to hold these same compounds. Included in this list of compounds are, for instance, X-nitrate, Poly Filters, molecular absorption discs, resins for chemical filtrations, and others. decide on the size of the compartment you will add, measure the exact dimensions of the acrylic pieces needed, obtain the pieces and make sure you have enough silicone sealer, use any one of the two designs below to build your compartment, place the compartment in the filter, and add the compound. Type 1 : Place the unit off the bottom of the filter by resting it on a ledge made of small blocks on all corners. For most efficient set up glue the corners onto the compartment. Use acrylic cement, or aquarium silicone. Place floss or screening on the bottom to prevent the material from getting through. Type 2 No base (bottom). The compartment rests on the bottom of the sump. Drill holes all around the base to let the water get out easily. Quarter inch holes usually will do. Remark : Clean the material regularly to prevent it from clogging and restricting the water flow. Remember to change the material that you are using in these compartments on a regular basis. Most exhaust themselves as they do what they are meant to do. Follow the manufacturer's instructions in this respect. If you do not attach (glue) the compartments permanently to the base of the sump, you will be able to remove them, and replace them with a larger (or smaller) one, should the need for that arise. Not attaching them will also simplify cleaning them, as all you will have to do is remove it (them). Always remove them very slowly, to prevent detritus trapped inside from getting into the sump of the trickle filter, and being sucked in by the pump(s). Fittings on the trickle filter : A good trickle filter should come equipped with all fittings needed to hook it up. This includes a fitting a the top, a hook-up for airline tubing, and one where the pump needs to be attached. It does not include ball valves and check valves, neither does it include float switches and the like, except perhaps in the top-of-the-line units. If the filter has a skimmer built-in, a hook-up for that should be provided as well. Again, make sure that the skimmer can be used with ozone if you are planning to do so, and that it is placed in such a way, that flowing the outcoming water over carbon is easy. It should also not allow air-ozone from getting into the back compartment where your biological medium is, as ozone will destroy the bacteria in the biological filter. To save on the total height, look for a filter that has a 90 degree angled fitting for the water inlet at the top. Float Switches : There are many uses in the Hobby for float switches. Level control is an important feature of a modern aquarium, and you should certainly consider adding it to your tank, especially since inexpensive models have now become available. Keep in mind that water levels can be controlled in various ways prevent water from getting too low, prevent water from rising too high, or a combination of both, using double switches. Float switches that control the "low" do two main things for your system's stability and protection : They prevent the pump from running dry when the water level in the sump gets reduced because of evaporation, or when you remove water yourself, for whatever purpose you may do so (for example when changing water). They even out (balance out) the amount of water going up to the tank, and the amount coming down to the filter as, if the level in the sump drops too much (you regulate the height at which the float switch triggers) because more is going up than coming down, the float goes down, and stops the pump for a short period, until the level in the sump goes back up. Float switches that control the "high" serve the following purposes : add from a reserve vat. When the level in the sump reaches the desired level (which you decide on) the float shuts the pump that is adding water down, remotely. Indeed, the pump is in the reserve vat, the float switch is in the sump, and senses the level as it goes up. shut down a solenoid valve that controls water coming a large skimmer to the sump, for instance. You are unlikely to use this feature in a basic system, however, because of the high cost of setting this up. A large and reliable solenoid (e.g. 1 inch in and outlet) costs close to $ 450.00. When in the market for a float switch, shop around! You should consider the following types that are commonly available: Reed switches Mercury switches Infra-red switches All have advantages and disadvantages : Reed switches are inexpensive, but harder to install, and may require that you operate them via a special relay. This does not make them very practical for the average Hobbyist to use. Mercury switches are more expensive. They are extremely reliable, but can be rather bulky and are not as easy to find. Installation is not difficult, but will take a little more time. Infra-red switches are very reliable, cost even more, but are extremely easy to install. If you are considering this type make sure that it can sense through the scuzz that builds up on the side of the trickle filter sump. Of course, they only work with transparent filters. The key when using float switches, is to make them trigger at the correct level. With mercury and infra-red switches this is real easy, with reed switches it is a little more complicated and time consuming. The trigger point should always be at least 1.5 inches above the top of the intake hole of the pump. This to prevent air from being sucked into the pump because of a vortex that will form around the intake area, if the level in the sump is too low. Air in the pump volute and impeller area, makes the pump run much hotter, and heats up the water too. Additionally the air may be broken up by the impeller, and extremely small bubbles may form. These are pushed into the tank, making it look real unsightly. Such small bubbles can also cause nitrogen gas bubble disease. Small, reliable, float switches can often be obtained from Marine Supply companies and shops. They are usually operated in conjunction with bilge pumps on boats. Make sure that they have no metal parts that can come in contact with the water in your sump, except if the metal is 316 SS. Additionally, they must be made to run on 110 volts, not 12 or 24 volts. [Albert J. Thiel requests that you make a $5.00 donation to the New Mexico School for the Visually Handicapped Children, 1900 North White Sands, Alamagordo, New Mexico 88310 (or other charitable group) if you download the entire book. This would be in lieu of the standard purchase price for this publication.] SMALL REEF AQUARIUM BASICS Hard Piping or Flexible Hose ? Although many Hobbyists prefer hard pvc pipe for all the hook-ups and connections, flexible hose is just as good and reliable. Additionally, if you source the flexible hose from a discount supplier, you will save quite a bit of money. You will still need ball valves and check valves, of course, but you can mail order those from companies such as U.S. Plastics in Lima, Ohio, or other ones that advertise in the aquarium magazines. Alternatively, get them from a local plumbing supply house, or from swimming pool places. Shop around! Prices can vary tremendously, as some of you may have found out. Hard piping requires that you familiarize yourself with how to glue PVC pipe together, and also which fittings will do the job you are trying to accomplish. Check the Marine Fish and Invert Reef Aquarium book, the chapter on Fittings, if you are not familiar with them. Flexible hose installations are usually simpler to perform, quicker to finish, but do not look as "tidy". Remember to always use hose clamps wherever you join flexible hose to an instrument, a device, or to pvc pipe and plastic fittings. This is most important to prevent leaks, and ensure that the hose will not slip off as a result of the internal pressure building up inside the system. If that happens to you, you will have a lot of water on the floor! Fittings other than on the filter : You will need at least one ball valve and at least one check valve per water line running back to the aquarium, to ensure that your system is totally safe. The ball valve will allow you to adjust the water flow going back to the tank from the filter, preventing too great a flow, and the check valve will prevent back syphoning through the line running up to the tank, should the pump break down, or should a power failure occur. More details can be found in my other two books as well. Shop around for these and other valves you may be using, as mark-ups vary widely from dealer to dealer, even from plumbing supply place to plumbing supply place. Place the ball valve about 1 foot away from the output of the pump (see diagram). Place the check valve either inside the trickle filter, or between the filter and the system's main pump. If you place the check valve inside the sump, right on the pump intake, you will be able to prime the pump (getting the air out) much faster and in an easier manner. When you do so, you should cover the intake side of the check valve with a special screen, which converts the check valve to a so-called foot valve. Depending on how elaborate your system is, or becomes, you may find it necessary to install more than one ball valve and more than one check valve. Refer to The Marine Fish and Invert Reef Aquarium, and also to Advanced Reef Keeping, for more details on how to set such systems up. Some type of installations need 2 lines of water flow, e.g. one to the aquarium and one to the protein skimmer. This is done by means of a Tee-fitting, either barbed, or straight PVC. You may then need a second ball valve to adjust the amount of water going to the skimmer. A typical installation, e.g. using the Thiel Aqua Tech filter, looks like this : Only one ball valve is shown in the return line to the tank. That usually suffices, but as an extra safety, especially to make servicing of the pump itself easier, you may want to include an inexpensive ball valve (usually called throw away types) between the pump and the sump of the trickle filter. This will allow you to take the pump out of service without having to lower the water level in the sump. Although they will cost more money, "true union valves" are a much better choice than regular slip/slip valves. They are also easier to maintain, can be opened, and allow for easy and quick disconnection of pipes, should the need arise. Adding Canister filters Earlier I referred to installing extra compartments inside the sump of the filter. Not everyone wants to go to the trouble of doing so, or may not need to, because they have one or more canister filters standing around from previous filtration systems. Canister filters obviously make great container/pump combinations for compounds through which the water needs to flow. I use them myself, and prefer the Eheim models 2217 and 2017 because of the large size of the canister itself. But there are, of course, other models available, for example Marineland's Magnum, and various Fluval types, including their large 403 model. Since we are trying to set up a Reef Tank that will be correctly equipped on a smaller budget, you may want to shop around for canister filters. Try the bargain newspaper ad in your area. Or check if your Pet Store can sell you used ones. Remember to change whatever compound you are using regularly. If, for instance, it is supposed to remove nitrates, as X-nitrate does, make sure that you test for nitrates from time to time, to double check whether your nitrates are still going down, or at least remain stable. If they do not, you obviously need to replace the compound. Using quick disconnect valves will make this a much simpler process. Flow rates through Filters and the Tank : First of all, you must differentiate between water flow through the system and water current in the tank. The former is pretty obvious: how much water is flowing through the filter, e.g. per hour. The latter represents the amount, and strength, of flow in the tank itself. They are not necessarily the same. In fact they shouldn't be. It is often recommended that you cycle the water content of your system anywhere from 2 to 6 times per hour through the filter. I find that latter figure much too high. My recommendation in The Marine Fish and Invert Reef Aquarium was, and still is, that the water content of the tank be flowed through the biological filter 3 times per hour. More, and you risk bacterial wash-off, less, and you may not get enough biological filtration. If you want more current in the tank itself, e.g. to simulate the wave action and movement around the Reef, use one or several power heads. One power head on the short side of the tank will usually do, but you can get more sophisticated, and use several that alternate, using an Ocean Motion machine, or similar. This was described in much more detail in Advanced Reef Keeping Made Simple. The key to get the right flow rate, is to select your pump carefully. Ratings for pumps are given, most of the time anyway, at 0 feet of head, meaning when no back pressure whatsoever exists.This can mislead you, inasmuch as you will be putting back pressure on the pump, and quite a bit of it, once you operate the tank . Here are just a few reasons for "head" (also called back pressure): Height difference between the level of the pump itself (where it is positioned), and the water return level (how high up the water is being returned, meaning to the tank. The type of pipe or hose used. Is it of the same size as the output size of the pump, or are you downsizing Are you downsizing the pipe or flexible hose elsewhere, is the intake pipe or hose the same as the pump fitting, are you using many fittings, especially 90o ells and 45o ells (angled fittings), as they reduce the flowrate greatly , are you returning the water to the tank from the bottom, or from the top of the tank, is the pump pushing water through canisters, or other filters, that restrict the flow, especially once they start plugging up, are you using a micron, or submicron, filter in-line ? Any and all of those, but usually a combination of them, added to frictional head, reduce the output of the pump, and result in the true output being quite somewhat lower than the stated output at zero feet of head. Frictional head is the head produced by the pipe or hose itself. You should therefore think carefully before buying a pump. More so even when you plan to use the pump to run additional devices that require a good flowrate as well, and put additional back pressure (head) on the motor. Talk to people in the Hobby that you respect, and whose opinion you value and trust, e.g. a Pet Store owner or employee, someone at an Aquarium Society, a manufacturer, etc. Explain exactly what you are planning to do, then decide on which pump to buy. Presently a lot of people use the Iwaki brand of pumps. I was responsible for introducing those pumps to the Hobby in 1987 on behalf of another company, and they had very good success with them. I have used many models myself, but have continued to look for a more aquarium specific pump, not one developed for the photographic chemical processing and similar industries. This has led my company to putting together our own pumps, The Tech - Z series, labeled Za, Zb, Zc, Zd and Zz, putting out respectively 300, 600, 900, 1200 and 2400 gallons per hour. All these pumps have totally encapsulated impellers (polypropylene), use a special form of cooling and run very "cool" as a result, and incorporate only Viton seals. All these pumps carry a full one year warranty to boot. Other brands you may wish to consider, US made ones, include Little Giant, March, Teel, and if you need a strong pump, Hayward. The latter only if you are using 1.5 or 2 inch pipe, and running a real large system. This is not something you would be doing on a small reef tank. For medium type flow rates I strongly recommend the "Aqua Pump", a 3-speed model that is excellent for running the kind of tank that we are looking at in this book. It is super quiet, can be adjusted for output, and is made of a combination of 316SS and a plastic volute, totally salt water safe. This is definitely one of the pumps to consider for smaller systems. It is also an excellent pump to run columnar skimmers with. I have used the Aqua Pump with 30", 46" and 84" skimmers, running the pump at respectively, 2nd, 2nd, and 3rd speed. In all cases it performed exactly the way I wanted it to and, combined with 2 airstones in the skimmers and a good air pump, it never let me down. You must keep one important fact in mind when selecting a pump : the life of the animals and invertebrates that you want to keep, and for which you paid good money, depends on the pump that you ultimately select, running 24 hours a day, for many many years, hour after hour, day after day, month after month. Do not overlook this, invest in a good pump. Don't take any chances. Pumps need to be cleaned from time to time, especially if its intake in the sump is not outfitted with a fine filter. Schedule it as part of your maintenance routine. Once every 3 months is probably a good time frame. Additionally, open and clean the pump and impeller, any time you know for a fact that a large piece of dirt got into it. Some general recommendations on installing and piping pumps: Do not reduce the output side (pressure side) of the pump right at the pump. If you must reduce it, do so at least 18 inches away from the output fitting on the pump. Never reduce the pipe going to the pump intake side (suction side). You will cause cavitation, and very small bubbles will always be visible in your tank because the water breaks up and the air comes out of it. Buy a pump with at least 25-30 percent more rated output than what you feel you will need to run your tank. This will help offset the pressure head loss in output, and give a better flow. Place the pump at the same level as the bottom of the sump. Not higher. Pumps sold for aquarium use do not "lift" water very well and you will strain the motor one one hand, and lose flow on the other, if you do. Additionally, it will be very difficult to prime the pump (get it started). Often pumps can be used in only 1 or 2 positions. Check to make sure that the one you are using is an allowable one. (horizontal, upright, at an angle, sideways etc.) Place pump on a thin piece of rubber, or foam, to reduce vibration and noise. Clean your pumps volute and impeller at least once every 3 months. Never let pumps run dry! You will hear this often, but it is still done. If you pipe the pump using hose barbs and flexible tubing, use clamps as well, to prevent the hose from being blown off the barb, because of back pressure. Preferably use a float switch to protect your pump. Make sure no water falls or runs on the pump. If it does, clean up the water as soon as you can. Salt water is highly corrosive, and will ruin your pump in no time. Protect your investment, take good care of your pump. Water Returns : One, Several, with or without bottom holes Water can be returned to the top or bottom of the tank, and you can use one or several water returns. How you set this up in your own tank will determine how you can populate the tank, as you do not want to cover up the water returns with rocks. In smaller to medium size aquariums such as the ones discussed in this book, one water return is enough. Whether you return the water from the top, or whether you pipe it in through a hole in the bottom is entirely your decision. Figures A B D (see previous page) Two water returns : the white hole is one, and the second one is through pipe, represented here by a thick black line. The entry point through the glass can be on the left, the right or the middle. In the former two cases you would use a 90o angled fitting coming out of the bulkhead (also called tank fitting), in the latter case you must use a Tee fitting, and capped-off pipe, going in either direction. The pipe in the middle, returns water underneath the rock formations and pushes the dirt out, so it can be filtered out or removed with a syphon hose, if you wish to do that. D shows the same arrangement, but with the pipe placed towards the back of the tan and the hole on the other side. Which configuration you use is entirely up to you. Figure C Three water returns : one on either side of the tank, and one underneath the rock formations to prevent water from stagnating there. The fittings used are described in A B D, above, and more details can be found in Advanced Reef Keeping I, also by Albert J. Thiel. As already indicated, most Hobbyists will not need to drill holes in their tanks and can safely return the water from the top. Angle the jets downwards to stir up the bottom layers of water and bring them to the surface for better re-oxygenation. Returning it from the bottom require more work, and the tank must be drilled. This is easy in an acrylic tank and somewhat more complicated in a glass tank. Some Pet stores now drill holes for you, or you can check with local glass dealers. As long as the bottom glass is not "tempered", drilling one or more holes is not really a problem. The positioning of the return holes varies depending on whose recommendations you follow. Here are two possible suggested ways. I use the one with the two returns, one under the rock, and one at one end of the tank returning water from the bottom, against a side pane. Sometimes spray bars are used to disperse the water over the water at the top of the tank. That may seem like a good idea, but it does not really create a great deal of water current and movement inside the tank. It should, therefore, in my opinion not be used in Reef Tanks. Corner Overflows or Syphons-Surface Skimmers? To bring the water from the tank to the filter, Hobbyists use either corner overflow boxes or automatic syphon surface skimmers. The use of corner overflows is rather widespread. Some tanks are sold with the overflow built-in, but more than likely, if you want to use that system, you will have to modify the tank. Again, you will need a hole in the bottom of the tank (or the back, or the side, but obviously inside the overflow arrangement). You will have to build the overflow by using either 2 plates of glass, or 2 plates of acrylic to make a square or rectangular box (or one plate to make a triangular box, another possible arrangement that is not shown). To affix the plates you will use aquarium silicone in glass tanks, and acrylic glue in acrylic tanks. Get plates of the same thickness as the aquarium glass or acrylic, using 3/8" as the maximum. This means that if your aquarium is made of 1/2S inch glass or acrylic, 3/8" will still do for the overflow. A 4" by 4" box is usually large enough for most tanks. Because of the work involved, and the difficulty that you may have in your area to get glass drilled (acrylic is easy, and you can do so yourself with a good hole saw) many Hobbyists resort to the use of a syphon surface skimming arrangement. There are quite a few on the market. Check around, and look for the following features : Can it handle the flow rate you are looking for ? Does it have a pre-filter built-in ? Can the pre-filter easily be removed and cleaned ? Is it glued properly, or do you see bubbles in the seams ? Is it easy to prime the first time you are using it ? Does it keep its prime, even if the pumps stop ? Will it fit over the ledge of your tank ? In glass aquariums such is usually not a problem, but in acrylic tanks with near complete tops, it often is. Will it skim the surface of the water in the tank and remove unwanted oily material, and floating particulate matter ? These are all important considerations. Do not select a model too hastily. Look for at least most of the above features, especially the automatic re-starting one (meaning it keeps its prime even if the pumps stop). Having a pre-filter that can easily be serviced is also important. Building your own is a consideration, but probably not worth the trouble. There is a large choice for you to select from, and in various price ranges. Buy only units that skim the surface properly, by means of a little box with indentations (tooth or comb-like) that hangs in the tank. If you are planning to run more than 350 gallons per hour through the surface skimmer syphon, the one you buy should have a 1 inch hose adapter going to the filter. If it doesn't you may not be able to run your pump at the speed you want. Of course, the unit you acquire should have a barb, or nip, in a convenient place (usually at the top), for you to be able to prime the syphon without much difficulty. The instructions should tell how to do so. Clean the pre-filter at least once a week, lest it will start restricting the water flow down to the trickle filter, which will result in your pump stopping if you use a float switch, or running dry if you do not, and possibly failing, or running very hot. Buy the right syphon-surface skimmer the first time around. You will save yourself both money and time, indeed, re-piping the system to replace the syphon is not something you want to look forward to. If you decide to drill holes, to return the water to the tank, which in my opinion is not necessary in small and medium systems, make them at least 3/4 inch pipe size. This means the hole will have to be 1 inch, to accommodate the bulkhead-tank fitting. Drip Systems as part of the Trickle Filter : Although not something that you will find in too many filters, it is a nice and helpful addition. Use them to dispense liquid carbonate hardness (KH) generators, vitamins, Kalkwasser (Limestone water), even fertilizer if you keep a lot of macro-algae. In most cases, and because drip systems can only be regulated down so low, you will have to dilute what ever product you are adding before putting it in the drip system. For more details on how to do so, and how to set up manual drip systems, we refer you to "Advanced Reef Keeping Made Simple" and also to "The Marine Fish and Invert Reef Aquarium" (6th or later printing), both by Albert J. Thiel. Improving the Efficiency of your Existing Filter Since many Hobbyists already own a trickle filter, we receive many phone calls at "Marine Reef", the newsletter published by Aardvark Press, enquiring how one can improve the efficiency of an existing system. Since we are setting up a Reef Tank using only the minimum basic equipment required, it is most important that all the components of this system run at their optimum efficiency. Here are a few suggestions : Blow more air into the biological chamber. Using regular aquarium air pumps, it is not possible to blow too much air in the chamber. Run the air through carbon first, to clean it. If you are not blowing air into it yet, start doing so, and make sure the drip plate is vented. Usually this is done by means of a piece of half inch, or three quarter inch, pipe sticking up from the drip plate. This will prevent an airlock from being created inside the biological chamber, should the water level in the sump rise to where the air can no longer escape through the bottom. If some of the media in the biological chamber is submersed, adjust the water level so it is out of the water. The efficiency of the filter will increase by over 50 percent. We guarantee it ! Clean the sump of accumulated debris and detritus, this will increase dissolved oxygen levels and improve the water quality, Switch to a different medium inside the filter. For example, if you are using DLS, switch to one of the plastic filtering media. We highly recommend Bio-Techs and Bio Blocks. If you are using trays with dolomite or crushed coral, switch to a plastic filtering material as well. If you don't switch, clean the trays one at time, to remove accumulated detritus, at one week intervals, to prevent the total loss of the biological filtering bacteria. Switch from a "spray bar" filter to a "drip plate" filter type; better gaseous exchange will take place, with the inherent improvement of the water chemistry, If you are already using a drip plate, improve its efficiency by using some, or all, of the recommendations we have made earlier. For example, increase the number of holes, but use smaller ones, and make the holes tapered. Add compartments for products such a Poly Filters, Chemi-Pure, X-nitrate, or whatever else you decide on using, including resins. Use one or more canister filters in addition to your trickle filter. Fill them with any of the above compounds, or use them for additional biological filtration by filling them with plastic filtering media. The efficiency of Bio-Techs, used in submersed form, is 65 percent of their efficiency in non-submersed form. A large difference, but still quite of a lot of extra biological filtration ability. If you are using ozone, make sure none of it is finding its way into the back chamber (biological chamber) of your filter. Ozone will destroy some, or all, of the bacteria, and will greatly reduce the efficiency of your filter in the process. Set up a reverse osmosis drip system, running the output of the unit directly into your sump. Use a very small unit, and do not let it run continuously. Use it to change water very slowly, and make up for evaporation at the same time. If you let it run for long periods of time, the water level in the sump will rise, and could overflow, unless of course you have a drain piped in. This is done by running a hose attached to a tank fitting, placed at the appropriate height, from the sump to a drain, or to a sink that is lower than the sump (e.g. in a cellar). If you do not have a drain, use a power head coupled to a float switch that kicks the pump on, when the level in the sump rises above a certain height. That water can then be pumped to a vat or sink, or wherever you can dispose of it. Always watch your salinity carefully when you are doing this, because you are adding fresh water, which will make your salinity go down slowly, but down nevertheless. Make up for this change in salinity, or specific gravity, at appropriate times. There are, I am sure, many other tried methods. If you have one that really worked for you, I would like to hear from you at Marine Reef, the Newsletter. We will compensate you for your contribution if it is published in the newsletter. In-Line Cartridge Canisters : These canisters, which can often be bought at do-it-yourself type hardware stores, and carry brand names such as Cuno, Water Kleen, AquaPure, etc. can be piped in-line with the water flow. Some even have a by-pass assembly built-in to the unit, e.g. the units sold by Thiel-Aqua-Tech, making changing the cartridge very easy, because it does not require you to stop the system at all. Alternatively you can pipe-in the by-pass yourself. Many types of cartridges for such filters are available : to remove rust to remove fine particulate matter, rated in micron ratings filled with activated carbon filled with a mixture of compounds to purify the water Keep in mind, when installing such in-line canisters, that they all put a lot of back pressure on your pump(s). This will reduce the water flow through the filters and through the tank. Micron ratings go in various sequences, usually <1 micron, <1<5 micron, 5 micron, 25, 50 etc. microns. You should also know the difference between absolute and nomimal ratings. Absolute means no particles of the size given, or larger, can go through the cartridge. Nominal means "most" of the particle of the size given will get trapped, but some will get through. Nominal rated cartridges are good enough for our purposes, and 25 or 50 micron rated ones should take out most of the free floating material that you may want to remove. Do not go too low in the rating, because you do not want to filter out all of the living organisms, indeed filter feeders need them for survival. Moreover, the finer filtering the cartridge performs, the sooner it will plug, and the sooner it will need replacing. That can add up to quite a few dollars, if you have to do so too frequently. Two types of such cartridges deserve special mention, they are manufactured and sold by Poly-Bio-Marine (through their distributors) : the PMA and PSM types, the former performing molecular absorption filtration, and the second one sub-micronic filtration. The one of most interest, in my opinion, is the PMA unit. They are specially tooled to be able to hold a number of disks, of Poly Filter material in disc form. Because of the way they are constructed, all the water has to go through the disks, before it can actually re-enter the main water stream. Because Poly Filters are so highly efficient, and because these canisters are easy to install and service, we highly recommend them. In fact, I personally use them on all systems I install, and of course on my own show aquarium. PSM canisters should not be used in continuous operation form in Reef tanks, because they remove all the material that filter feeders need. You should pipe them in so you can run them for a few hours, and then by-pass them without having to stop the system. See the diagram on the next page for one method of piping in such a by-pass. The first canister shown could be any type, and is not required. It is shown here, because many Hobbyists use both PMA and PSM canisters in-line, one after the other. The first one should be the micronic, and the second one the molecular absorption one. The first one removes very fine particulate matter, and the second one acts as an extremely efficient chemical filter. Remember to take the PSM cartridge off after you by-pass it, otherwise the water in the canisters will go anaerobic, and the next time you try to use it, you will push all that anaerobic material in the tank. Such is very dangerous for your invertebrates, and even for the fish you keep. With a properly set up by-pass, this problem does not arise. Just unscrew the bottom of the canister, rinse the bags inside, empty the canister and replace it. The above diagram shows that you can isolate one or both canisters, meaning by-pass just the first one, or both, by switching the valves around. Under normal circumstances you would run the first canister, e.g. with a cartridge filter of, for instance, 25 or 50 microns, or a PSM module, and the second one with Poly Filters, X-nitrate, or some similar product. Remember the remark about emptying the micron filter when it is not in use, to prevent the formation of anaerobic by-products. If you don't, the next time you place it back in line (use it) all these anaerobic compounds will end up in your system, and will create a great deal of stress on the tank life. It will greatly reduce your redox potential, reduce dissolved oxygen levels, and may even kill off some of the tank life. Automatic Float Switches We already covered float switches earlier. There is, however, one switch on the market that is both very reliable (over 100.000 operations) compact, and inexpensive that you may want to consider for your system : the Thiel-Aqua-Tech Super Float, which at the time of this writing retailed for $ 76.00. It comes in a molded housing that you place into the sump, at the appropriate height, and connect into the pump wiring, as shown in the diagram. It can be used for inductive loads (e.g. pumps in our case) up to 5 amps, 110 volts. It should be affixed to the bottom of the sump, or vat, by means of a suction cup, or a little aquarium silicone. If it needs to be placed off the bottom, on a ledge of some sorts, because of the amount of water you keep in the sump, affix it to that ledge. Note the following : Only two wires come out off the Super float molded box. Some switches may have more wires, find out from the supplier which ones you should use to control the low, or high, triggering operation. Only one of three wires that make up the pump lead that ends with a plug is used. Check the diagram carefully before wiring the switch in. The pump lead is the cord that comes off your pump. This is called a splice, and where the connections are made, electrical tape has to be used to insulate the connections and make them water tight. Never attempt to wire the Super float, or any other float switch while the pump is plugged in ! You will get an electrical shock. Do not submerse the part of the electrical cord where you have made the splices, and covered them with electrical tape. If you acquire the Super Float, do not operate it with pumps that draw more than 5 Amps. Check for the rating of other switches with whomever you bought it from. Operating a device at more than the rated amperage will ruin the device, in a short period of time, and can in some cases cause serious electrical shock. The Super float, or any other float switch for that matter, must be placed in the sump, at the appropriate height. The installation of switches can sometimes be cumbersome, e.g. the orange german one available on the market. The Super Float is merely placed in the sump, on a base, if necessary, to adjust the height in deeper type sumps. Incidentally, 100 000 minimum guaranteed operations of the switch, corresponds to about 5 years of continuous usage, with the switch going on and off about 55 times a day. That is most unlikely, on average, switches operate perhaps 10 to 15 times a day, if that much, greatly extending the guaranteed life of the switch. Any pump can be operated with a float switch, including a power head type pump. Anything that works with electricity, in fact, can be operated with a float switch, providing , of course, that it makes sense to do so. Besides a pump, you may want to operate a solenoid that controls some outside device with such a switch. This is, however, not part of the basic system we are looking at in this book. Converting from an Undergravel to a Reef System While on the subject of biological filtration, let's review how one can convert a traditional undergravel system to a Reef Tank. Many Hobbyists, and you may be among them, already have a tank set up, either a fish-only, or perhaps even an aquarium with a mixture of fish and invertebrates, installed with undergravel plates, and perhaps one or several canister filters as well. Transforming such a system into a more modern one, using a trickle filter, is quite uncomplicated. There are basically two major approaches : Maintain the undergravel system, while adding a trickle filter, Do away with the undergravel filter altogether. You may elect to keep the canister filters, yet fill them with different compounds, e.g. chemical filters, as we shall see later. Both are viable approaches, but the second one is the better one of the two, because it takes a potential area of low oxygen and pollution out of the system, while improving the overall quality of the biological filtration considerably. You may want to start with method one, let the tank run for a while in that fashion, and convert to a full Reef system at some later date. Maintaining the Undergravel : Design the system you would like to end up with. Lay it out on paper, so you know what kind of parts and components you will need to acquire. Make sure all the parts will fit inside the aquarium cabinet. Measure carefully ! Obtain an appropriately sized trickle filter, taking the recommendations made earlier in this book into account. Select an internal medium. Use one of the many plastic/ polyethylene ones now offered for sale. Some Hobbyists use plastic haircurlers. This may work, providing you use the clear ones that cannot leach a dye into the water. It would be safer however if you used a more traditional type of biological medium, e.g. Techs, Blocks, Spheres, Balls, Rings, Cubes, etc. There are plenty of them around. Determine the quantity you need, based on the suggestions made in this, and other books. Obtain a surface skimming syphon, preferably one that will re-start automatically, and keep its prime, even if the power and/or pump fails. This will make it unnecessary for you to re-prime it. If you do not have one, buy a pump, and if you can budget for it, a float switch as well. It protects the pump and the system itself. If you are not getting a protein skimmer right now, start thinking about it, because you will need it to maintain adequate water chemistry parameters. In light of this, you may want to get a filter with the right sized, ozone safe and resistent protein skimmer built-in. Flexible vinyl, or acrylic, hose piping is an excellent way to go, and requires less time and expertise to install. Clamp all flexible hose connections to prevent slippage due to pressure, and leakage. Install the filter and all other components of the system. Do not forget to blow air into the biological chamber of your trickle filter. This is important for the potency (meaning how effectively it will perform) of your biological filter. Use a good, strong air pump. We suggest a Whisper 1000 or a pump with an equivalent output. Fill the sump of the trickle filter with salt water, and start the pump, after priming the syphon of the surface skimmer. Check all connections to ensure that you have no leaks. If you do, fix them now. Usually just tightening a clamp will do the job. If need be, adjust the water level in the sump . Sometimes the pump will push up water so fast, that the sump water level becomes a little too low, and air gets sucked into the pump. If you have a float switch installed, the pump will shut off before that happens, providing you have set the float to kick on and off at the right level. If not, now is the time to adjust it, so it triggers at the correct level. We have not mentioned the undergravel yet, because we do not want you to change anything to it, at least not yet. Let the system run on both the undergravel, and the trickle filter, for one week to ten days. Because of the biological activity going on, and bacteria populating your new trickle filter, acidity is produced. This will affect both your carbonate hardness and the pH of the water. You should not worry about this, except if the pH goes down to dangerous levels e.g. 7.6 - 7.7. If this happens, you should add a carbonate hardness generator to your tank's water, preferably a liquid one, or a powdered, or tablet form, that does not make the protein skimmer foam excessively and starts overflowing. Since your undergravel is still operating as it was before you added the trickle filter, water quality, as far as ammonia and nitrite are concerned, should not be a problem. In fact, if you had any before, you should'nt now. You have a better filter! After 7 to 10 days you need to give your undergravel filter a serious cleaning. In order not to disturb the total undergravel biological filter, however, clean only 50 percent of the filter (e.g. one side of the tank, or just one plate if you have several). After cleaning the undergravel filter, perform a 15 percent water change, and another 10 percent about 6 hours later. Now wait another 7 to 10 days, and clean the other half of the undergravel filter. Again, perform a 15 percent water change after the cleaning is completed, and a 10 percent water change approximately 6 hours later. Next, reduce the flow of water going through the undergravel filter. Do not stop the flow through the undergravel completely ! You would be creating an anaerobic environment very quickly if you did. Just slow the flow down to a minimum, much lower than what you had before. The reason for this, is that at a lower flow, detritus will not be pulled into the undergravel so easily, and no oxygen, or at least much less, will be taken out of the water by detritus breaking down in the under-gravel filtration system. Your tanks water will, as a result, have a higher dissolved oxygen and redox potential level. Check for ammonia and nitrite throughout the switch-over period. It is unlikely that any significant amounts will be found, although you may detect more of it than you normally would for a few days, especially right after you clean the undergravel filter. Your switch-over is completed, and you now have a modern reef system. Clean your undergravel every 2 months or so, to remove detritus that may have accumulated. Converting and Removing the undergravel : In the interest of maximizing water quality, it is much better, filtration-wise, when converting to a modern Reef System, to remove the undergravel filter completely. This may not be as practical as the previous solution, but it is definitely more efficient, and to the benefit of all tank lifeforms, especially the more sensitive corals and invertebrates. Because of the nature of dolomite, or crushed coral, and the usual size in which it is sold as undergravel filter material, it easily traps detritus as water is pulled through it by the up-lift tubes and by, power heads. In fact more so with the latter. Many Hobbyists will remark that reverse flow is a much better way of operating such filters, because the water can then easily be pre-filtered before it is pushed back through the filter bed itself, and into the aquarium. That is of course entirely correct, but detritus still gets trapped. It is just of a smaller size, and the clogging process will take longer to occur, but occur it will. Just stir up an old undergravel filter bed, and you will agree with me that the material that you can see coming out of the filter bed, cannot really be conducive to the higher water qualities that we are looking for in a Reef aquarium. We are not saying that undergravel filters do not work, they do of course. If they did'nt, the hobby would not be where it is now. What we are saying is that you can do better, improve the water quality significantly, by removing the undergravel and switching over to a trickle filter as the sole biological filter of the tank. The steps involved in doing this are similar to the ones described in the previous section, up to the point where we recommend that you clean half of the undergravel bed thorougly. Instead of waiting 7 to 10 days, wait 14 days, meaning let both the undergravel and the trickle filter run the tank for 2 weeks, then remove half of the undergravel (or in larger tanks remove one third) including the plates. This is labor intensive work for which you must plan, as it may take quite a while to do. After the plate, the crushed coral and dolomite are removed, perform a 20 percent water change. Wait about 6 hours, then perform another 10 percent water change. Since you may have two (or more) plates to remove this whole process may take up to 30 days to complete. Change plates at 10 day intervals, and perform water changes each time, as indicated. The easiest way to remove the dolomite, or crushed coral, is to syphon it out with a large diameter hose. This will reduce the amount of material (detritus and mulm) getting into the water. You will be removing water at the same time, which you need to do anyway, because of the recommended water changes. Watch the pH, and add a carbonate hardness generating fluid (or tablets, powders without binders), if it drops too low. Beware of products that contain nothing else but baking soda ! Remarks on the Conversion Process : Because in both types of conversions the existing undergravel, and the new trickle filter, are running at the same time, the seeding of the new filter with bacteria is automatic, and the cycling happens without the Hobbyist noticing it. Indeed, you already had a lot of bacteria in the system. They are being transferred to a different medium. As long as the existing undergravel filter was able to keep ammonia and nitrite down to zero, no increase will be noticed in the first 7-14 days, while both filters are running together. After cleaning the undergravel (in one scenario) and removing part of it (in the other), a small amount of ammonia and nitrite may be present for a few days. The amount will, however, not be high and stress on the fish will be minimal. There will be some degree of stress that the animals will have to cope with, that is unavoidable, indeed, you are making changes. Do not add any fish or invertebrates whatsoever during the conversion process! None whatsoever. Clean all mechanical filters before you start the conversion. To alleviate stress on the tank life change your Poly Filters if you are using them already. If you are not, we suggest that you add 1 Filter per 25 gallons of water in the system. To find that number, add the volume of water that is in the sump, to the gallon content of the tank. Multiply that by 90 percent (to account for displacement by rocks etc..) and use that number. Remember that the water going to the trickle filter needs to be pre-filtered. If you don't do so, you will have to clean the drip plate of the filter regularly. Good quality syphon surface skimmers will have such a pre-filter built-in. If you are using a spray bar, which we recommended you did'nt, pre-filtering is even more important. The recommended water changes that go in hand with the cleaning of the undergravel filter, and removing the plates, are very important. They are meant to remove the noxious toxins that result from stirring up the material used on the filter plates, from the water. Not doing so may lead to a lot of problems. In the first type of conversion, where the undergravel filter is not removed, you must clean the undergravel filtering medium very thoroughly, to remove any material that can cause oxygen depletion, anaerobic activity, plugging of the crushed coral or dolomite, etc. In the second type of conversion, where the undergravel is removed in several stages (at least two), it is very important that the medium on the filter plates be syphoned out. This will prevent the detritus in the crushed coral, or dolomite, from mixing with the tank water. Some of it will, but you must try to minimize that mixing as much as possible, because of the toxins it also contains. Remember not to turn the undergravel filtering system pumps (air or power heads) completely off. Reduce the throughput, but do not shut it off completely. If you do, the layer of water underneath the plates, and the material on the plates, will quickly produce anaerobic by-products. This may kill off everything you keep in the tank. Many Hobbyists have made that mistake before you, and have wondered why, even though they added a trickle filter, they could not raise the water quality. Do not rush the conversion. Take your time. Follow the suggested timeframe. Your fish and invertebrates will benefit from it. If you were using canister filters in conjunction with your undergravel filter, you can certainly continue to use them with the new filtration you installed. It seems, however, that they should then be used for other purposes : additional mechanical filtration (clean them at least once a week), chemical filtration (see next section), special compounds e.g. to remove nitrate from the water, etc.Run them, taking water from the sump, and returning it to the sump. Because of the changes you are making to the filtration, initially, changes to the water chemistry will affect the redox potential; it will go down, but come back up after a few days, to a week maximum. Dissolved oxygen and carbon dioxide levels will also be affected, but not to the point where you have to be concerned about it. Changing over to trickle filtration is a positive move. It will take time to perform, but it will greatly benefit your system in the short, and long run. It definitely is a positive step for the water quality, and ultimately for how your tank will look some weeks down the road. [Albert J. Thiel requests that you make a $5.00 donation to the New Mexico School for the Visually Handicapped Children, 1900 North White Sands, Alamagordo, New Mexico 88310 (or other charitable group) if you download the entire book. This would be in lieu of the standard purchase price for this publication.] SMALL REEF AQUARIUM BASICS Chemical Filtration General Remarks This is probably the least understood form of filtration that is required in fish-only as well as in Reef tanks, even more so in the latter. Mechanical filtration removes particulate matter of varying sizes; biological filtration removes ammonia and nitrite by means of bacterial processes, and converts it to nitrate; chemical filtration removes yet other types of compounds, some of which are not normally removed by the former, some of which are not removed by protein skimmers either (see next section). The best known form of chemical filtration is activated carbon, others include molecular absorption filters (e.g. Poly filters), resins (e.g. HyperSorb), and special compounds meant to selectively remove certain elements from the water. What kind of compounds are we talking about? Besides the undesirable elements already mentioned, e.g. free floating material, nitrogen breakdown intermediates, seawater absorbs many noxious elements from the surrounding air (e.g. nicotine, tar, fumes, perfume essence, volatile organic compounds etc..), chemicals that, when they accumulate, can stress the tank life considerably. Besides these, many chemical compounds are formed in the aquarium and are not removed by the filters already mentioned. Included in this category are, for example, yellowing matter (gilvin), organic acids, heavy metals that may come in with the tap water, pesticides in very small quantities (ppb's), etc. The principles of chemical filtration are based on molecule adsorption, and on ion affinity, allowing certain compounds that we add to the filtration system to remove unwanted elements very efficiently. Because we do not "see" the filter at work, certainly not as much as we can determine what a mechanical filter is doing for example, these type of filters can be extremely beneficial, especially if the material used is replaced on a regular basis. I conducted many experiments along the lines of chemical filtration, using an assortment of chemical filtering materials. All work, some much better than others. Two types in particular are very familiar to most hobbyists : activated carbon and Poly Filters. Resins and other compounds are used less frequently, except perhaps for the "X-nitrate" compound from Thiel-Aqua-Tech, which is very specific for Nitrate ions, and can lower the total NO3 in seawater to the 2-5 ppm range in a matter of 7 to 10 days. Unlike carbon, this product cannot be regenerated. Then again, regenerating carbon is not recommended anyway, as Hobbyists do not really have the equipment to do so efficiently. Activated Carbon Many types of carbon are sold in Pet Stores. Unfortunately the Hobbyist has no way of knowing which ones are good, bad or better. Some brands are merely charcoal (usually shiny) and are very ineffective at removing noxious compounds. You should definitely avoid them in Reef Aquariums. Other types are "activated", a process that substantially increases the porosity of the carbon, and as a result greatly increases the total active surface area, usually depicted in drawings as an intricate path of holes, and channels in the carbon, allowing it to be much more effective at adsorbing compounds that need to be removed from the Reef tank's water. The amount of pores and channels is what is of interest to us. Activated carbon has a maximum adsorption capacity, which is the reason that it should be replaced from time to time. How frequently is hard to determine, because it is dependent on the quality of the water that is flowed through the carbon. Note that we said flowed "through" and not over. Your activated carbon will work much better if water is actually forced to go through the amount used, rather than just flowed by, and over it. More contact between the activated carbon and the water obviously results in a more efficient cleansing process. One problem that frequently occurs in saltwater tanks with a heavy organic load, is that the outside of the carbon becomes quickly coated with organic matter and slime, preventing further uptake and adsorption of unwanted compounds from the water. How much carbon you should use, if you decide on this m