Moss & algae killer plus surface cleaner ready to spray size 32 ounces Attaches to hose end. Herbicidal soap dries out the moss and algae. Use on decks, fences, roofs and lawns to eliminate moss, algae, lichens and grime. Treats up to 500 sq. ft.Attaches to hose end. Herbicidal soap dries out the moss and algae. Use on decks, fences, roofs and lawns to eliminate moss, algae, lichens and grime. Treats up to 500 sq. ft.