Algae Bugger II is indispensable! Great for cleaning sand and DE filters as well as cartridge filters. Simply attach Algae Bugger II to a garden hose and it will blast scum lines to oblivion. Algae Bugger II reaches the deepest pores and works on concrete, vinyl, acrylic, fiberglass and tile. Perfect for around step areas and in corners. Algae Bugger II features a convenient on/off switch located on the handle.