Filter for a Waterfall

Waterfall Basics

• An outdoor waterfall generally consists of a submersible pump, sometimes called a pond vault, that collects water. Water enters the pump and flows through a pipe, generally made from flexible polyvinyl chloride pipe. The pipe leads to the spillway, positioned higher than the vault at one end of the pond or basin. Water falls out the spillway through rocks, decorations or directly into the pond, where the waterfall pumping cycle begins again. Pumps and filters can also be integrated into one unit.

Filter

• When buying a filter, ensure it's correctly rated for the size of the water area in gallons. A filter designed for a basin holding 700 gallons will not work if your pond holds 2,500 gallons. The most economical filter is integrated with the pond vault and uses a solid grid of plastic or metal to mechanically prevent debris and large particles from entering the pump. The filter, pump and tubing can easily be dropped into existing ponds. Because all parts are clearly visible, you can easily lift the filter for maintenance and cleaning. The unit may also contain a finer mesh, either at the vault or at the spillway, to remove organic elements.

Skimmers

• Skimmers are more expensive units, designed to work on the surface of the water. Most contain the water pump as well as the filter, which then requires a pipe to the spillway. Because much of the unit sits above the surface of the water, it must be disguised with rocks, plantings or garden sculpture. No plumbing appears inside the water, making for a nicer appearance. A skimmer is generally easier to clean and offers better filtration. However, it's more difficult to install since it involves positioning at just the right height, as well as disguising.

External Filters

• The most expensive option puts a skimmer at the water's surface, a pipe to a separate filter unit and then another pipe from the filter to the spillway. These systems are designed for larger ponds, ponds under trees or other heavy sources of debris -- or ponds with heavy organic loads such as those containing koi. No plumbing appears in the water, making for better esthetics. However, the units above the water and on the ground require hiding. Installation is more difficult than with skimmers alone, but these systems offer the best filtration. The skimmer and filter can also be cleaned separately, making for easier maintenance.