Safer Brand 5324 Moss and Algae Killer and Surface Cleaner, 32 oz. Hose Sprayer This all-natural algae killer utilizes the natural effectiveness of potassium salts to rid your deck, roof, siding, walkways, lawn and more of algae and moss Ready-to-use formula attaches directly to your hose for an economical and convenient organic solution to your algae problem Kills algae, mosses, lichens, liverworts and grime OMRI Listed and compliant for use in organic gardening Contains potassium salts of fatty acids (40%)