External pressure filters. Allow flexibility in locating your pond filter. These filters can be placed further away from the pond or can be partially buried to hide them in the landscape. These filters vary in sizes and will suit from small to very large ponds. External pressure filter consists of a canister that is connected thru a pipe with a separate pond pump. These filters can be mechanical and biological and can come with an ultraviolet clarifying unit. Additionally, more complex pressure filters have backwash ability.

External gravity flow filters. In external gravity filter water is pumped from the pond into the filter and flows back into the pond by gravity. These filters typically have a filter sponge for mechanical filtration and permanent biological unit. These pond filters are easily maintained and installed and must be placed above the water level of the pond, usually placed at the pond’s edge. This filter consists of a canister and a separate pond pump. Some gravity filters come with a UV unit.

Internal submersible filters. Commonly used in small ponds and water features. Most internal filters have mechanical and biological unit, a UV clarifier and a pump to circulate the water. Many submersible pond filters include a fountain kit.