So, you ask, "How do I get algae out of my pond?" Most UV sterilizers kill bacteria and blooming algae (not string algae) from inside a unit that sits outside of your pond. The unit you choose is connected by plumbing hoses from your pond and hidden by landscaping like fake rocks. Choose 10W of UV light per 1000 gallons to clarify the water or 30W of UV light per 1000 gallons to eliminate green and sterilize the water.
The Savio UVinex UV Clarifier lets you fit a UV bulb or two inside a Savio skimmer. Another option is Oase FiltoClear's built-in UV clarifier filtration unit. Outlets and such can be hidden by a fake stump or rock, as well.