Fritz Algae Clean Out stops algae growth dead in its tracks! Excessive algae growth is one of the most common hazards to both the beauty and the health of aquariums of all sizes. Algae Clean Out by Fritz is the most concentrated EPA registered algaecide solution available today. String algae, blanketweed, and green water caused by single-celled algae are among the most common algae targeted and destroyed by Algae Clean Out. While this algaecide is of exceptional power, it also contains no copper (common among rival algaecides) and is very focused in scope, leaving your live plants and fish inhabitants unharmed when used as directed. Works great with all kinds of habitats, from freshwater and saltwater aquariums to fountains and ponds.