UV light sterilization passes water through a tube with a UV bulb inside. A UV water sterilizer removes floating algae and, with slow water flow, sterilizes many aquarium parasites like ich. UV sterilization is a great strategy for managing pests and improving water quality. While a small tank can use an internal or submersible UV sterilizer, most hobbyists use an inline UV sterilizer that attaches to a return hose. UV bulb replacement should be done once a year.
