AlgExit combats green algae in freshwater aquariums such as beard algae brush algae and string or thread algae. It is harmless for fish crustaceans and plants. Dosage Rate: Use: Shake before use. Add 10 ml per 100 litres once a week for four weeks. This period may be extended if algae still remain or if spores continue to germinate. For prevention: 5 ml per 100 litres once every two weeks. Remove active carbon. Warning: Use biocides with care. Active ingredient: salicylate. Do not add too much. Keep out of the reach of children and pets. Only for use in freshwater aquariums