Salt
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[edit] Salt (Sodium Chloride - NaCl)
Sodium chloride is essential to life on Earth. Most biological tissues and body fluids contain a varying amount of salt. The concentration of sodium ions in the blood is directly related to the regulation of safe body-fluid levels. Propagation of nerve impulses by signal transduction is regulated by sodium ions. (Potassium, a metal closely related to Sodium, is also a major component in the same bodily systems).
Salt is used in the aquarium hobby for several reasons.
- Adjusting the salinty of water for brackish water or sea water animals.
- Additive in freshwater tanks to aid the occupants due to osmotic pressure
It should be noted that the use of domestic 'table salt' is not recommended as this product often has unspecified anti-caking agents and other chemicals in it. Raw sea rock salt is generally acceptable. Though always check the product's ingredients.
Most freshwater plants do not tolerate any level of salt in the water and will soon perish.
- Pure freshwater with no salt has a specific gravity of 1.000
- Brackish water is often quoted as being a specific gravity of around 1.005
- Sea water has a specific gravity of around 1.020 to 1.024 (3.5% salt)
[edit] Using Salt
| Per Litre | Per Imperial gallon | Per US Gallon | |||
| Use | Recommended strength | grams | Level teaspoons (tsp) | Level teaspoons (tsp) | Time |
| Mild Ammonia/nitrite protection (often used for shipping fish) | 0.1% | 1g | 1 | .75 | 12-48 Hours |
| General additive - nitrite protection (Brown Blood Disease) | 0.3% | 3g | 2.75 | 2.5 | 12-24 Hours |
| General heal, fungicide, repair of tissue | 1% | 10g | 9 | 7.5 | 12 Hours |
| Short-term salt dip to remove parasites | 3% | 30g | 27 | 22.5 | 30secs to 10 minutes (check species) |
| Levels of salt for different classifications of water types | |||||
| Brackish water | 0.5-30g | - | - | - | |
| Marine sea water | 35g | - | 28 | - |
(1 teaspoon = 4.7 grams, 1 tablespoon=14.2 grams)
[edit] Marine Salt
Salt used for Marine or Coral aquariums is not plain Sodium chloride. But is in fact a complex recipe of many different types of salts. Various commercial mixtures of salt are available, all claiming to be the perfect salt for making up artificial sea water.
Typical commercial mixture for making ~1 litre of sea water:
| Chemical | Weight in grams |
| NaCl Sodium chloride | 23.477g |
| MgCl2 Magnesium chloride | 4.981g |
| Na2SO4 Sodium sulphate | 3.917g |
| CaCl2 Calcium chloride | 1.102g |
| KCl Potassium chloride | 0.664g |
| NaHCO3 Sodium bicarbonate | 0.192g |
| KBr Potassium bromide | 0.096g |
| H3BO3 Boric acid | 0.026g |
| SrCl2 Strontium chloride | 0.024g |
| NaF Sodium fluoride | 0.003g |
Then add pure water to make the final weight 1Kg.
This yields sea water of salinity 34.5‰, pH between 7.9 and 8.3.
(reference - Marine Aquaria book page 4 by L.A.J.Jackman, F.Z.S member of the Marine Biological Association U.K. Crediting Mr. F.A.J Armstrong and Dr. Wilson of the Plymouth Laboratory)
[edit] Animals that don't like salt
There are several species of freshwater fish that do not tolerate salt in the aquarium and these are listed here.
[edit] Animals that may prefer a level of salt in the water but can live without it
- Mollies
- Platies
- Indian Glass fish
- Certain Puffer species
[edit] Fish that need a level of salt in the water and can not live without it
[edit] References
[edit] Aquarium Wiki Articles
- The Salt of the Earth by Robert T. Ricketts

