AQUATOP's Aquarium Scrubber is designed for use in glass aquariums (not safe for acrylic aquariums) to manually remove even the most stubborn algae from the glass viewing panels. Easy to use heavy duty glass scrubber. For fresh and saltwater. Removes Algae for a clean surface. Ergonomic handle for maximum pressure. SPECIFICATIONS AND SAFEGUARDS For glass aquariums only, do not use on acrylic aquariums. Use caution when scrubbing glass near the substrate not to allow any sand or gravel between the scrubber and the aquarium wall. This may cause scratching. Always rinse the aquarium scrubber under freshwater from the faucet after each use.