A UV water clarifier attachment engineered specifically for Fluval FX series canister filters. This compact 6-watt UV unit easily connects inline with the FX filter, exposing circulated water to ultraviolet light. The UV sterilization helps eliminate free-floating algae (reducing green water), as well as harmful bacteria and parasites, resulting in clearer, healthier aquarium water. It runs safely inside the filter loop without exposing fish to direct UV. Using the FX UVC clarifier is a chemical-free way to maintain sparkling water and reduce pathogen levels in large aquariums. (Fluval FX Series 6W UV Clarifier)