Green Water Clearer Aquarium 4 litre (formerly Conditioner & Clearer Aquarium)Green Water Clearer Aquarium helps to condition water and clear unsightly green matter. When used strictly as directed, it is harmless to filter systems and can be used without harmful effects to fish or plants. Directions: Add 5ml to 200 litres of water. For severe cases, use 10ml to 200 litres. This should clear water over approximately 3 to 10 days. To prevent green matter recurring, repeat dose every 5 to 6 weeks or when necessary.