AQUATOPs submersible UV sterilizing pumps use an innovative method for eradicating and controlling free-floating microorganisms and disease-causing pathogens. The built-in pump draws in water, exposing it to the 5-watt or 7-watt UV bulb which sterilizes and clarifies the water. Unlike typical UV sterilizing systems, it is easy to install and requires no special plumbing so you can quickly experience a crystal-clear aquarium.