To make De-chlorinator concentrate
Weaker solutions can be made for smaller betta containers The shelf life of the solution is about six months when stored in a cool location. If you use Bleach to steralize your Aquariums or equipment or if you Decapsulate your brine shrimp eggs, this is an inexpensive way to neutralize the Bleach. Mix 1 tablespoon of Sodium Thiosulfate in a pint (8 oz) of Water. Add one drop of the solution to each gallon of water to remove 3.75ppm chlorine.
BLEACH & Chlorine Neutralizer : SODIUM THIOSULFATE DECHLORINATOR
Sodium Thiosulfate, Na2S2O3, is a colorless crystalline compound, also called sodium hyposulfite or “hypo”. It is soluble in water and is a mild reducing agent. The crystals will keep for several years if kept dry.
Thiosulfate will break the bond in Chloramine between the Chlorine and the Ammonia, and it binds Chlorine and most heavy trace metals.
The ammonia which is left behind should be in nominal amounts. However, you should test the ammonia level in your tap water after treating it. Ammonia test kits may give false readings if there is excessive amounts of Hypo in the tested sample.
A high level of ammonia is toxic to bettas. Symptoms include: Increased mucus layer on fishes mucus membrane, Swollen gills, Fin rot, Flicking against hard surfaces, Gasping at the surface of the water, Inability of fish to maintain its balance in the water.