Aquarium Filter with UV Light 7W is a submersible sterilizing unit with pump that can be installed in either an aquarium or filter sump.  It eradicates disease causing pathogens, free floating micro-organisms, and green water algae helping to make your aquarium cleaner and safer for its in habitants.  It also provides extra filtration, oxygenation, and water circulation along with being able to utilize a venturi diffuser and spray bar at the same time.  A brilliant and useful supplementary filter for any aquarium.  This 7W model is suitable for aquariums up to 270 litres.