Carbon is an essential element used by aquarium plants for photosynthesis. API CO2 Booster supplies a concentrated source of carbon in two forms: CO2, as well as simple, organic carbon compounds. CO2 Booster may be used alone or with a CO2 system. CO2 Booster is safe for use with freshwater fish and will not alter pH. 1 ml treats 10 gallons. Dose once a day.