A pond filter is required to clean and filters pond water. Pond filters are extremely important if your pond occupies any type of fish or aquatic wildlife - especially Koi or goldfish. Pond filters should be a combination of biological and mechanical filtration.
Biological filtration works to break down fish waste and organic matter using beneficial bacteria, while mechanical filtration captures particles in a physical filter so they can be removed when the pond is cleaned. The ideal pond filter will have both biological and mechanical filtration components. Your pond filter should also be compatible with UV clarifiers to achieve algae control. Pond filters are priced according to their size and power - typically ranging from $300 to $2,500 online.