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Since November 97 I've tried something new. My plenum with live sand is moved

down to the approximately 15 gallon RDP Refugia with three Mangroves. So the

bottom of my 75 gallon tank has nothing but an inch of white Oolitic sand from

CaribSea. I increased the flow though this setup and all seems to be working

fine. I like the white sandy beach effect in my tank. It shows off the colors

of everything.

Mark Peterson, Treasurer

Wasatch Marine Aquarium Society

Salt Lake City, Utah

801-296-1556

            CONTROL OF NIGHTTIME pH AND ALGAE FOR A HEALTHY AQUARIUM

           by Mark Peterson      Salt Lake City, Utah      April 1997

      "That's a lot of algae" is what many people say when I show them my Reverse Daylight

Photosynthesis (RDP) tank. I was inspired by John Walch head of R&D for the Aquatic Wildlife

Co. in Tennessee and one of the principle designers of the "ecoReef "(RDP) aquarium system.

He visited our club, the Wasatch Marine Aquarium Society, in December 1996 and I started my

RDP tank a few weeks later. It's located underneath my 75 gallon reef tank and has a lush growth

of filamentous and macroalgae.

      Photosynthetic production of oxygen stops in darkness and plants become oxygen users

rather than oxygen producers. The Reverse Daylight Photosynthesis tank creates a nighttime

source of oxygen and utilization of carbon dioxide which keeps the pH up in my reef tank after

the lights go out. It also doubles as a Refugium; a place to grow algae and all the organisms that

live in the algae, which fish love to eat. I harvest caulerpa every few weeks giving it away to

my friends who are also starting their own RDP tanks. It's not necessary to grow caulerpa but it

grows fast and I like to grow the different types. (Some algae are more efficient oxygen

producers requiring less space than caulerpa.)

NO SHRINKING CORALS

      It works. The carbon dioxide absorbed by the RDP tank keeps my corals out at night and

not shrunken by morning. As an example, a Flower Anemone (which by the way looks exactly

like the one pictured on the last page of the Practical Guide to Corals for the Reef Aquarium by

Ed Puterbaugh and Eric Borneman) showed a striking increase in size and health since the

change. It was about 4 inches in diameter and would shrink to 2 inches and now it stays about 5

inches day and night. The pH used to fall below 8.0 by morning and when the lights came on

would rise in a couple of hours to 8.3. Now the pH always stays above 8.1. The pH swing from

day to night has been cut in half and now remains within the levels recommended by the experts.

I imagine that the ocean pH varies much less but at least it's getting closer to natural.

FISH WITHOUT ICH

      Also noticeable in my aquarium is the health of my fish. I have an Eyespot Damsel that

used to have a problem with the dreaded Ich. The spots were often visible on its body in the

morning twilight. As the lights came on the parasite would gradually retract into the body. The

damsel would frequently scratch against objects. Those symptoms are completely gone! All the

fish appear healthier.

      When John Walch showed us his technique and commented that he likes green plant

growth I listened up and immediately set about planning my RDP system. The purpose of this

system is to absorb carbon dioxide and to provide oxygen. The simplest way to do this is to

simulate night during our day and day during our night. The length of the day isn't so important

but the plants in the RDP tank need to be photosynthesizing when the plants in the main

aquarium are not. It appears to me that the algae grows so well in the RDP tank that it's not able

to grow as well in the reef tank!

      A unique characteristic of my marine aquarium is the quietness. I don't like the noise of

water gurgling and splashing. Only two powerheads move water within the tank and although

they are placed to shoot water at each other across the surface, it just isn't enough to completely

exchange oxygen and carbon dioxide with the atmosphere at night. The consumption of oxygen

by coralline algae and the carbon dioxide production by bacteria in the lower levels of the

aragonite, I believe, combine to create the need for this new system. Of course it's not a new

system, it's an old technique that John Walch inspired me to try. I tried it and it works great.

SKIMMER ELIMINATED

      Here's something else. I haven't run the skimmer since long before the RDP was started

and I've only changed five gallons of water in four months! My tank is flourishing. I have soft

corals like never before. (No hard corals in this tank.) The Mushroom Anemones still shrink

down in the dark but by day they grow to a four inch diameter rather than their former two inch

size. The mushrooms are also reproducing by pinching off and by sending out little arms of flesh

from the base that separate as one centimeter baby mushrooms.

      Other organisms in the aquarium are various leather corals, Xenia, Sinularia, Anthilia

(Woods polyps), and what was a tiny old Condylactis anemone which has grown to one foot in

diameter in 4 months (luckily it has remained on the same rock). Here are some details about my

75 gallon aquarium:

      Plenum with 3" of course CaribSea aragonite live sand

      Live rock - about 65 lbs.

      Two actinic 4 ft. flourescent tubes

      Two 5000K  4 ft. flourescent tubes

      Ten fish of about 2 - 3 inches

      40 "Reef Janitor" crabs & snail (plus 100's of baby snails)

      Two powerheads on the water surface

      SeaChem Reef Complete, Reef Calcium and Reef Plus added per directions.

      Nitrate level - less than 2 ppm

      Calcium level - above 450 ppm

      No Kalkwasser!

      KH level - 7 degrees dh

The RDP tank is a 35 gallon opaque plastic storage container to which I added:

       1/2 inch layer of aragonite live sand which helps when harvesting caulerpa

       One powerhead pushing water up to the reef tank

       Two 2 ft. plant growth flourescent tubes

The tubes and non corrosive reflector are attached to the underside of the lid which

remains closed.

      I am grateful to John Walch for speaking at the Wasatch Marine Aquarium Society

meeting and being willing to share this kind of information with us. His experience is invaluable

and he welcomes inquiries. He may be reached c/o The Aquatic Wildlife Co. 15042 N. Moon

Valley Dr., Phoenix, AZ 85022. Telephone: 602-548-8697, FAX 602-862-9061. E-Mail:

AquaWildAZ@aol.com.

      The switch to a plenum and the NNR / Live Sand method of filtration in my aquarium

began about three years ago. I too am one of those hobbyists inspired by Tom Frakes' Fall '93

SeaScope article about Dr. Jaubert's "Red Sea Reef Mesocosms in Monaco". Unfortunately, I

don't know how he avoided what I believe was happening in my tank. I believe that a general

lowering of pH was occurring at night in my aquarium using the NNR/Live Sand filtration

system. (This may also occur in aquariums with other types of filtration though I'm not sure

because people don't normally check pH at 5:00 AM.) The condition became more prominent as

time passed and the algae gained more and more ground until I experienced the typical "crash"

overgrowth of algae. I AM HAPPY TO REPORT THAT I EVENTUALLY BEAT THE ALGAE.

SAVING MY CORAL REEF

      Green. Just green. As far as the eye could see was green in my reef aquarium before we

dumped in the little "Reef Janitors" in January, 1996. Where once beautiful live rock had colored

the tank, my hobby was being choked to death by a flowing mat of hair algae. The hair algae had

completely covered the live rock. Where once pink and purple coralline algae had brightened my

aquarium, now only green hair flowed in the current. It was two inches long, covering everything

and waving as though it were the green hair of an ugly mermaid. The substrate was likewise

covered. Each little piece had a mane of long hair algae. My best efforts at physically removing

it were frustrating, to say the least. For two years this algae had been gaining ground. I was at the

point where I was ready to throw in the towel and go back to my African Cichlids.

      It was an innocent call one cool day in the Fall of '95 that brought the little "Reef

Janitors" to my aquarium. Little did I know that a call to Leroy Headlee of Geothermal

Aquaculture Research Foundation (GARF) of Boise, Idaho would result in the saving of my reef.

Leroy had been featured in the Spring 1995 issue of SeaScope about "Live Rock Aquaculture." I

asked him to come speak to our club, the Wasatch Marine Aquarium Society of Salt Lake City,

Utah.

      The beginning of the end of my reefs' destruction began on the day after Leroy's

presentation at the January meeting. It was a day of rebirth... for my aquarium that is. Leroy

graciously offered to leave me with more than 300 Reef Janitors to test their power and to keep

them on consignment until needed by shops in Salt Lake.

      My coral reef was saved from utter destruction by these Reef Janitors, which are tiny red

legged and tan legged hermit crabs and three kinds of snails from Mexico that eat hair algae and

cyanobacteria algae. Their use in the aquarium was discovered by Leroy Headlee and he

distributes them through GARF (telephone (208) 344-6163, FAX: -6189, web page:

www.garf.org.

      The introduction of the Reef Janitors came just in time. During the first ten days small

patches of coralline algae began to reappear. The crabs would climb to the top of a bulge of rock

and pick it clean. During days 10 to 20 (the first month) the hair algae would reconquer some of

those hills, but gradually, owing to the strength and number of these little soldiers, the second

month saw more and more rock and substrate taken by my Reef Janitors. The algae was losing

ground and "we" were winning! (200 of the janitors were sold and gone by the end of six weeks) 

      The snails should also receive their praise. Where before I had to scrape green algae

from the glass at weekly intervals just to see my ugly mermaid, the snails immediately attacked

the problem. They did so well that the next glass scraping was at about 10 weeks because of a

buildup of tougher algae. But this was not nearly the same visibility problem as before. The

coralline algae was growing again and it was growing on the glass too.

THE NUTRIENT PROBLEM

      Of course, there was a nutrient supply which created the algae problem. Two years of

feedings without any real attempt to remove nutrients was the culprit. I never vacuumed because

vacuuming disturbs the NNR system, yet I hadn't done anything about the grayish colored "crud"

which had accumulated at sites around and under the rocks. Phosphates were abundant but

nitrates had been less than 5 ppm since a change to the Jaubert / Natural Nitrate Reduction

(NNR) or Live Sand method more than a year before.

      The aquarium had been converted to the NNR method nearly one year prior and

operated successfully during the switch. I simply moved the power heads away from the

undergravel uplift tubes and 10 days later removed the tubes allowing the substrate to fill in the

resulting holes. Nitrates dropped from 25 ppm to 10 pm gradually over three weeks. A couple

months later, after I added a skimmer, the nitrates leveled out at around 3 ppm.

THE SOLUTION

      Several actions on my part helped the Reef Janitors reduce the algae. 1) I used a

mechanical, sponge filter to strain out the uneaten bits of algae that became free floating after

the crabs snipped them off. 2) I began using phosphate remover which I had never used before.

3) I turned off the lights and covered the whole aquarium with a dark bed sheet for the whole

day several times weekly for the first month which seemed to facilitate the last step. 4) I

removed all algae and "crud" that a 3/8 inch diameter siphon hose could pull off the rock at

weekly water changes.

      Any one wishing to try the Reef Janitors should not be intimidated, thinking that the

main reason this worked so well for me was the sheer number of little workers I had at my

command (I was fortunate that Leroy Headlee offered to set up this experiment in my aquarium).

My hair algae problem was enormous, but if I had started with the recommended one crab per

two gallons of water my two year growth of algae would have taken, perhaps, six months to

clear. I personally recommend buying 2 or 3 per gallon and then selling the extras when they've

done their job. They are tidal zone inhabitants, so are very hardy in transport out of water from

one tank to another.

      Reef Janitors prefer hair algae and also red and blue-green (not black) cyanobacteria. I

discovered that in the absence of their prime food they will eat decorative algae and may even

become cannibalistic when competing for a limited supply of algae. They may eat a tiny amount

of coralline algae, especially some softer varieties, so, if you don't have an algae problem, use

more snails than crabs. The snails are best for cleaning softer algae from glass/acrylic and rocks.

      Finally, I believe that the miracle cure for one of the marine algae problems has been

found. REEF JANITORS ARE TO THE REEF AQUARIUM WHAT THE PLECOSTOMUS IS

TO THE FRESHWATER HOBBY. They saved my reef and allowed it not only to regain, but to

improve, its life and color.

      There is bright hope for our captive reefs and encouragement that the coral reefs of the

world can be saved.

Mark Peterson, Treasurer

Wasatch Marine Aquarium Society

Salt Lake City, Utah

(801)296-1563, FAX: -1564 email: mrpslc@aol.com (starting 3/98 @wfol.com)