Sodium thiosulfate appears as white, translucent crystals. It is soluble in water, insoluble in alcohol, absorbed in moist air. Commonly used in photography as a fixing agent (hypo) to dissolve unchanged silver salts from exposed negatives. Also as chlorine remover (dechlor) in bleaching and aquarium and pond water treatment.
Used in the following patina formulas:
Sodium thiosulfate readily forms colorless, monoclinic crystals. Read our article, "Growing Large Crystals with Seed Crystals" for more information.
Sodium Thiosulfate as Pond/Aquarium Dechlorinator
Chloramine vs. Chlorine...
The following stock solution of Sodium Thiosulfate does not treat for Chloramine, only Chlorine. Chloramine is a chemical compound composed of chlorine and ammonia and more and more utilities are converting to its use. Check with your municipal water company to learn which chemical they are using. If Chloramine is the disinfectant, please research other knowledgeable sources to learn your best solution for water treatment.
To begin...
Obtain a clean one gallon jug. A photography supply store will likely have good brown jugs. They are used to store darkroom chemicals. Dissolve the 500 grams of Sodium Thiosulfate in a large pitcher of lukewarm tap water. Stir until all the crystals are dissolved. Then transfer the solution with a funnel to the gallon jug. Top off the jug to make a full gallon of stock solution.
- Add 2 drops of the stock solution per 1 gallon of the water to be treated.
- One gallon can treat 37,850 gallons or more. Over-dosage is virtually impossible.