Pondmaster Clearguard Pressurized UV Pond FilterThe Pondmaster Clearguard Pressurized Pond Filter with UV Clarification incorporates mechanical and biological filtration to keep your pond looking clear and clean, and uses a UV clarifying agent to prevent the growth of algae. This all in one filtration unit is easy to use and makes it simple to keep your pond looking great. Heavy duty pond filter Provides mechanical and biological filtration UV clarification helps keep water algae free Easy