Ocean free absolute co2 48 tablets is used directly in the live planted tank. Quick result and effective, soon after using this algae controller, the algae growth will come out as debris. If you tank is full of algae, you can reduce the water level in your tank first and use this algae controller by way of spray by needle or spray kit (water sprayer kit which we use in our garden). Provide daily co2 requirement. Assist in co2 photosynthesis process. Enhance aquatic plant size and hasten the growth. Allow co2 to be more common and readily to be used for medium/ small tanks. 48 Tablets in a bottle.