GreenClean Granular Algaecide An EPA- registered, non-cooper algaecide that kills existing string algae on contact! Unlike other aquatic algaecides on the market today, GreenClean works on contact to control algae in water gardens, ornamental ponds, fountains, and other water features. GreenClean does not harm fish and aquatic life, and starts working instantly! Through its patented formula, GreenClean immediately begins fighting algae blooms, releasing vital oxygen into the water body as it biodegrades. A 2 lb container will treat a 1000 gallon pond for an entire season: 8 lbs will treat a 4000 gallon pond for a full season. With heavy growth of algae, recommended dosage is up to 1/2 lb per 1000 gallons.