There are two very powerful natural sterilizers, ozone and ultraviolet (UV) radiation.If you're serious about protecting your aquarium fish and invertebrates use Ozonizer or ultraviolet Sterilizer to protect your aquarium against harmful organism.Sterilizer- ozonizer or ultraviolet is a proven,dependable and effective method for controlling disease-causing pathogen bacteria and algae control in your aquarium and create crystal clear water.