Originally Posted by iGoatfish
Aquarium salt is evaperated seawater. and spicific gravity a very accurate way mesering the amount of salt in water. But thanks for trying.
Yes, specific gravity is a very accurate method of determining the salt concentration. And you asked, so.....
From what I've seen recommended on this site, the amount of salt recommended for treatment on this website ranges from 1 to 3 teaspoons per gallon. For this calculation, I'll go with the higher dosage of 3 teaspoons per gallon.
The water used in freshwater aquariums is NOT pure water. There are some dissolved salts in it already. That said, I have no way of knowing the specific gravity of your particular water, so I'll do the calculation using PURE water (H2O). The density of pure water is 1.000 g/mL at 4C.
I don't know the exact makeup of "Aquarium Salt," but people here appear to be referring specifically to sodium chloride. (I've seen it listed online as both NaCl, and as 'evaporated sea water.') I'll use pure NaCl for the calculation to simplify things. (If you want it redone later using evaporated sea water, let me know.)
One U.S. teaspoon of pure NaCl has a mass of approximately 6.1 grams NaCl.
Adding three teaspoons of NaCl to 1 gallon of PURE water would result in 18.3 g NaCl added to 3,785 g H2O. This would provide a 0.48% NaCl solution.
Assuming that the volume of 18.3 g NaCl dissolved in 1 gallon pure H2O is negligible, this would result in a density of 1.0048 g/mL at 4C. (Keeping to three decimal places, this would be 1.005 g/mL at 4C).
Or, if you prefer, the recommended dosage of NaCl in pure H2O would yield a specific gravity of 1.0048 at 4 degrees C.
However, the above calculations were done at 4C. For Bettas, whose tank is closer to 79F (26C), the density of pure water is closer to 0.997 g/mL. (Keeping to three decimal places.) So you'll need to take into account the temperature difference between 4C and your fish tank (approximately 26C) when you determine the SG.
water: the density of sea water ranges from approximately 1.020 to 1.029 g/mL, depending on temperature, and contains 3.5% salt. (At the surface, the average density of sea water is approximately 1.025 g/mL.) Thus, there is MUCH more dissolved salt (of various types, not just NaCl) in sea water.
Personally, I'd find it easier to just add 1-3 teaspoons of Aquarium Salt into a gallon of the tap water that I use for the Betta's tank, if my fish needed treatment.
And I would find it difficult to measure the tiny increase in specific gravity using anything I have at home, but you may have equipment sensitive enough to do this....
Thanks - I enjoyed this opportunity to do some calculations. LOL. I've been a little bored today.
(Various internet sources were used to look up information.)