King British Green Water Control targets the tiny unicellular algae in your fish tank that cause "green water". This special additive causes the algae to clump together and fall to the bottom of the tank, where they can be more easily removed. "Green Water" is unsightly, can clog filters, and can be bad for fish health, as it can reduce oxygen availability at night. For use in coldwater & tropical aquariums. One 100ml bottle will treat 900 litres of tank water.How to useShake bottle well before use. Using the pipette add 1ml of Green Water Control for every 9 litres (2 gals) of water. Alternatively, add 1 capful (4ml) of Green Water Control for every 36 litres (8 gals) of water. For best results the pH of the aquarium water should be between 6.5 and 8.5. Continue filtration during treatment but remove filter carbon. Repeat treatment every 14 days while problem persists. When water has cleared, remove dead algae from the bottom of the tank and clean the filter. A 10% water change is recommended after the problem has been terminated. Renew filter carbon. Contains Synthetic organic polymer.To help control algae growth check the following:The tank is not too close to a windowThe lights in the tank are not too powerfulThe lights in the tank are not being left on for too long (fish should not usually be exposed to more than 8-10 hours of artificial light each day)Fish are not being overfedAny dead plants and uneaten food are removedThe filter is clean and working correctly Treats up to 900 litres 200 gals.Health & SafetyStorage:Store the bottle in this carton in a cool, dry place.Do not store above 25 degrees centigrade.Warnings:KEEP OUT OF REACH OF CHILDREN.READ ALL INSTRUCTIONS BEFORE USE.DO NOT USE IN MARINE AQUARIUMS