Sodium Thiosulfate Calculator
Amount to be treated Amount of Sodium Thiosulfate
Gallons Liters ppm Chlorine Ounces Grams

Why Dechlorinate? Chlorine damages and can kill your fish! The bottom line is this: If you add any water, you need to dechlorinate. Chlorine/chloramines are toxic to fish. Declor is cheap.
If your water contains only chlorine, then sodium thiosulfate is an excellent and inexpensive dechlorinator. Remember, always dechlorinate tap water,whether you're replacing 1000 gallons or just 5 gallons.
Calculator Usage: Enter the amount of water to be dechlorinated (gallons or liters) and the ppm chlorine you need to detoxify.
You probably noticed that this is most useful when filling a pond or making a large water change. For normal use, it is much easier to simply make a Stock Solution, i.e., a solution that treats x amount of water with y amount of the stock solution. Y
Examples: You plan to add 1000 gallons to your pond, how much ST is required?
Enter 1000 in the gallons field and let's say you expect 1ppm chlorine, so enter 1 in the ppm field. This will show you that you should use 13.262 grams or 0.469 ounces. It is always best to err on the high side as ST is not toxic at even double or
Notes: This calculator uses JavaScript.
I'm confident this calculator is accurate, but things happen. Use it at your own risk,
Calculators Provided by Koi and Water Garden Society of Central New York