How to Hook Up Pond UV Lights & Filters

Updated February 21, 2017

A pond or water garden creates a miniature ecosystem in your yard. The plants and fish in a pond support each other, with the plants providing oxygen and the fish fertilising the plants. An ecosystem such as your pond needs to be kept in balance, or the fish and plants can become sick. Algae in the water disrupts this balance and clouds the water. You can get rid of this problem is by hooking up pond UV lights and filters to help keep your water crystal-clear. Determine the size of your pond, then purchase the appropriately sized filter, pump and UV light.

Install the pond pump according to the manufacturer's instructions. Pumps can either be submerged or external. Shelter external pumps from the rain and sun. Submerged pumps are less expensive, but they aren't as efficient as external pumps. Plug the pump into a GFCI (ground-fault circuit-interrupter) outlet. These outlets protect against electric shock by cutting off the circuit automatically if they detect a voltage leak. Connect the outlet hose on the pump, if present, and secure with a tie or hose clamp. Insert the inlet hose into the pool on external pumps. Submerged pumps don't require oulet hoses.

Install the filter. Filters can also be submerged or external. If you're installing a submerged filter, it should be placed on the bottom of the pond. External filters should be placed near the pond pump.They can be concealed with shrubs or rocks if you wish to hide them from view. Connect the tubing for the filter to the inlet on the pump. Secure it with a hose clamp or tie.

Install the UV light. The UV light has one side for the water inlet and one side for the water outlet. Make sure that it is aligned properly when you install it. It should have an arrow indicating the proper direction of water flow. Connect the UV light to the side of the filter. Secure it in place with a hose clamp or tie. Plug the UV light into the GFCI outlet. Connect the other end of the UV light to a inlet hose for the pond. Secure it in place with the clamp or tie.

Turn on the pumps. If this is an external pump, it must be primed first before starting.


If you have a preformed pond liner, its size will be stamped on the liner or listed in the owner's manual. Pond pumps are measured by the number of gallons of water they move per hour (gph). Your pond water should be circulated at least once per hour. For example, if you have a 150-gallon pond, you'll need to purchase a pump with at least a 150-gph capacity. Filters come in different sizes for different pond dimensions. UV lights are measured in terms of wattage; larger ponds need larger wattages. It may take some time for the UV light to begin clarifying the pond, especially in ponds with a heavy algae population. If you do not have a GFCI outlet, you can convert an existing one to GFCI yourself -- if you feel comfortable working with electricity -- or you can have a professional do it for you.

Things You'll Need

  • Hose clamps or plastic ties
  • Tubing
  • Scissors
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About the Author

Nathan McGinty started writing in 1995. He has a Bachelor of Science in communications from the University of Texas at Austin and a Master of Arts in international journalism from City University, London. He has worked in the technology industry for more than 20 years, in positions ranging from tech support to marketing.