Smartpond Pond and Fountain Algaecide, 16-Ounce Treats up to 3,000 gallons Do not use unless you have String Algae Must have continuous aeration Please remember this product is used for only STRING algae and not for green water or some buildup on the side of your pond Safe and non-toxic for plants and fish, this great product is available in different sizes so you can purchase the amount you need for your pond