Inorganic Substances as Additives in the Marine Aquarium

John W. Linville, D.V.M.

As an alternative to commercial trace element additives, I would like to detail the possibility of making one's own solutions of the most common trace elements: calcium, strontium, iodine and bicarbonate.

Part III: The Data Smorgasbord

Following are several tables and lists of various measures, conversions and other useful data.

Natural Seawater Values

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Key:

Element: _WeightAbreviation^{Ionic Form} = Concentration

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Sodium: _22.9898Na⁺ = 10,770 ppm

Chlorine: _35.4530Cl^- = 18,880 ppm

Magnesium: _24.3050Mg²⁺ = 1,290 ppm

Sulfate: _96.0576SO₄^2- = 2,712 ppm

Bromine: _79.9040Br^- = 67.3 ppm

Fluorine: _18.9984F^- = 1.3 ppm

Boron: _10.8100B³⁺ = 4.5 ppm

Calcium: _40.0800Ca²⁺ = 412.1 ppm

Potassium: _39.1020K⁺ = 399 ppm

Strontium: _87.6200Sr^2- = 7.9 ppm

Silicon: _28.0860Si⁴⁺ = 2 ppm

Carbon: _12.0110C⁴⁺ (as CO₃^2-, HCO₃^-, CO₂) = 28 ppm

Nitrogen: _14.0067N^3-,3+,5+ (as NH₄⁺, NO₂^-, N₂, NO₃^-) = 15 ppm

Iodine: _126.9045I^- = 60 ppb

Most all other elements can be found in seawater as trace elements in the parts per billion or smaller range.

Salinity and Specific Gravity

Full salinity seawater contains 35 to 37 parts per thousand (ppt) salt.

35 ppt = 35 g per liter = 4.7 oz per gallon = 2.9 lbs per 10 gallons

True specific gravity (sg) of full strength seawater (35 ppt) is 1.026.

Aquariums are generally kept at a salinity of between 30 ppt and 33 ppt (sg = 1.022 to 1.024).

Fish from the red sea require water with a salinity of about 34 ppt or a specific gravity of 1.025.

Metric and US Measurement Conversion Factors

Temperature

US to Metric:

C = (F - 32) / 1.8

• 32 F = 0 C
• 80 F = 26.6 C
• 212 F = 100 C

Metric to US:

F = (C x 1.8) + 32

• 0 C = 32 F
• 26.6 C = 80 F
• 100 C = 212 F

Liquids

Metric to US:

• 1 cubic centimeter (c³; cc) = 1 ml; approximately 20 drops
• 1 milliliter (ml) = 1 cc; 1/1000 liter
• 1 liter (l) = 1000 ml; 1.06 quarts; 2.1 pints

US to Metric:

• 1 teaspoon (tsp) = 5 ml; approximately 100 drops; 1/6 fluid ounce
• 1 tablespoon (Tbs; tbsp) = 3 tsp; 1/2 fluid ounce; 15 ml; approximately 300 drops
• 1 fluid ounce (fl oz) = 2 Tbs; 6 tsp; 29.6 ml
• 1 cup = 8 fl oz; 236.8 ml
• 1 pint (pt) = 16 fl oz; 2 cups; 473.6 ml
• 1 quart (qt) = 32 fl oz; 2 pt; 4 cups; 946.3 ml; ~ 0.95 l
• 1 US gallon (gal) = 128 fl oz; 8 pt; 16 cups; ~ 3.8 l; 0.833 UK gallons
• 1 UK gallon = 1.201 US gallons

Concentrations:

• 1 percent (%)= 1 ml or mg per 100 ml
• 1 part per thousand (ppt) = 1 g per 1000 ml; g/l
• 1 part per million (ppm) = 1 ml or mg per 1000 ml (1 liter); ml/l; mg/l; 3.78 mg/gal
• 1 part per billion (ppb) = 1 ml or mg per 100,000 ml (100 l); micrograms per liter

Weight

Metric to US:

• 1 milligram (mg) = 1/1000 g
• 1 gram (g) = 1000 mg; 15.4 gr; 0.035 oz
• 1 kilogram (kg) = 1000 g; 35 oz; 2.2 lbs; 1 liter of pure water

US to Metric:

• 1 grain (gr) = 0.65 g
• 1 ounce (oz) = 28.35 g
• 1 pound (lb) = 16 oz; 454 g; 0.45 kg

Length

Metric to US:

• 1 micron = 1/1000 mm
• 1 millimeter (mm) = 1/10 cm; 1000 microns; 0.039 in
• 1 centimeter (cm) = 10 mm; 0.39 in
• 1 meter (m) = 1000 mm; 100 cm; 39.37 in; 3.28 ft

US to Metric:

• 1 inch (in) = 25.4 mm; 30.48 cm; 0.3 m
• 1 foot (ft) = 12 in; 30.48 cm; 0.3 m
• 1 yard (yd) = 3 ft; 91.44 cm; 0.91 m

Tank Volume

Rectangular or Square Tank:

• US gal = (length (in) x width (in) x height (in)) / 231

• Liters = (length (cm) x width (cm) x height (cm)) / 1000

• UK gal = (length (in) x width (in) x height (in)) / 277.42

Cylindrical Tank:

• US gal = ((diameter (in))² x 0.8 x height (in)) / 231

• Liters = ((diameter (cm))² x 0.8 x height (cm)) / 1000

• UK gal = ((diameter (in))² x 0.8 x height (in)) / 277.42

Hexagon, Octagon, Multisided (sides of equal length) Tank:

• US gal = (((total perimeter (in) x width of single side (in)) / 2) x height (in)) / 231

• Liters = (((total perimeter (cm) x width of single side (cm)) / 2) x height (cm)) / 1000

• UK gal = (((total perimeter (in) x width of single side (in)) / 2) x height (in)) / 277.42

Sources

• Mergus Meerwasser Atlas, Band I: Hans A. Baensch, Helmut Debelius

• The Marine Aquarium Handbook: Martin A. Moe, Jr.

• Chemistry. A Conceptual Approach: Charles E. Mortimer