The safest and most effective way of neutralizing chlorine and bleach in all fresh and salt-water aquarium applications. It also the most cost effective way of preparing aquarium and pond water.
Dechlorinating Tap Water: One level teaspoon (tsp) of Sodium Thiosulfate treats 250 gal of municipal tap water. Prepare stock dechlorinating solution by dissolving one level tsp of crystals (about 4 grams) in 1 oz (30 ml) of water. Use at a rate of two drop solution per one gal of tap water. For very large aquariums and ponds, appropriate amount can be dissolved in a cup of water and entire cup poured into aquarium or pond.