IceCap In-Sump UV SterilizerUltraviolet Light Aquarium Water Clarification Made Simple The IceCap UV In Sump Sterilizer helps keep your aquarium healthy by reducing the spread of harmful microorganisms from fish, coral, invertebrates, and other aquatic life. It does this without using chemicals. It also helps control free floating algae, parasites, bacteria, and fungi in saltwater and freshwater aquariums. When installed and maintained correctly, the high output UV light kills