Bio-Kleen Hull Clean is a fiberglass hull and pontoon marine cleaner. Quickly, efficiently and safely cleans and removes algae, lime, scale, soap scum, chalking, rust, corrosion and other mineral deposits from acid resistant surfaces with very little effort. Designed as an aggressive, spray-on, spray-off cleaner that dissolves deposits and gives you the best economy when pulling boats out for storage and detailing. A safer alternative to harsh acid. Aromatic: No harsh fumes or burns. Will not harm gel coat. Use on: fiberglass boat hulls, boat props, outboards, stern drives, aluminum, pontoons and anodes.