Fluval 3W UVC In-Line Clarifier quickly and easily connects to most canister filter setups, eliminating suspended bacteria and algae for a clear and healthy aquarium. Its compact, low-energy design sterilizes water as it flows through, using ultraviolet light to kill green water algae and harmful microbes. The result is crystal-clear water and improved water quality, achieved with a safe, low-pressure UVC system that is easy to install and operate.