From The Aquarium Wiki
Sodium bicarbonate is a chemical compound with the formula [[NaHCO3]]. Because it has long been known and is widely used, the salt has many other names including sodium hydrogen carbonate and "sodium bicarb," as well as baking soda, bread soda, saleratus, and bicarbonate of soda.
- It prevents pH Shock disease in areas of soft tap water.
- It can be used to make tank water more alkaline as it will buffer water up to a pH of 8.2.
- One teaspoon (~5 grams) of sodium bicarbonate per 189.3 Litres (50 US G.) of water will increase KH by about 1 degree.