chemical formula: Na2S2O3
( powder )
Sodium Thiosulfate, a very versatile chemical, is commonly known as 'Hypo'.
It is a photographic fixer that's used for both film and paper developing. It's also used in the tanning of leather, chemical manufacture, water assessment, and in treating Cyanide poisoning. It's also very good at removing Iodine stains.
Sodium Thiosulfate is used to lower Chlorine levels in swimming pools and spas following Super Chlorination. It's also frequently used to dechlorinate tap water for aquariums, and treat effluents from waste water treatments prior to release into rivers.