Acurel F is the preferred choice of professionals for keeping aquarium water crystal clear. Fast-acting and easy to use, Acurel F clears cloudy, green or polluted water within hours of application. It combats the harmful effects of overfeeding and improves filter efficiency, resulting in a crystal clear environment for your fish. Safe and effective, it will not disturb the beneficial bacteria in biological filtration systems of healthy established aquariums. Acurel F is MADE IN THE U.S.A. with organic extracts from renewable resources. It is safe for all freshwater fish and plants, and environmentally friendly. To clear cloudy water: Acurel F is super concentrated. Just add Acurel F directly to the aquarium. Use 2-4 drops per gallon (5 liters) of water. For best results, leave your aeration and filtration systems ON. The water should clear within hours. Add more Acurel F if the clearing is incomplete. To maintain a crystal clear aquarium: On a daily basis, add 1-2 drops of Acurel F per gallon of water, directly to the aquarium. For best results, leave your aeration and filtration systems ON. To improve aquarium filtration: Acurel F dramatically improves the efficiency of most aquarium filters. Professionals know that the daily addition of 2 drops of Acurel F per gallon of water directly to the aquarium will assist filtration and maintain a crystal clear environment for your fish. For best results, leave your aeration and filtration systems ON. Clouding caused by adding new gravel: Just add Acurel F directly to the aquarium. Use 2-4 drops per gallon (5 liters) of water. For best results, leave your aeration and filtration systems ON. When cleaning or maintaining old aquaria: Use 2-4 drops per gallon (5 liters) of water. For best results, leave aeration and filtration systems ON.If an excessive amount of Acurel F is used, the water may become brown for a few days. This is NOT harmful and will disappear in a few days. Use only in fresh water aquaria. Do not use with brackish water species in fresh water.