Purpose of Pond Skimmers | An Introduction To Pond Surface Skimmer Filters

What is a Pond Skimmer and why is it important to a garden pond?

In its simplest terms a pond skimmer filter is a mechanical pond filtration system that removes leaves, grass cuttings and other vegetation that can be found, floating on the surface of your fish pond. They are particularly useful during autumn (fall) when trees start to shed their leaves; usually into your pond, unfortunately!

A pond surface skimmer doesn’t simply remove the pond surface debris so as to maintain the look and feel of your fish pond. By removing excess pond surface debris it also helps to ensure that the debris can’t fall to the pond floor and form sludge; thereby removing the opportunity for unwanted bacteria colonies to form. The build up of these heterotrophic bacteria encourages fish disease and the release of toxic gases, such as hydrogen sulphide.

Heterotrophic bacteria are often responsible for causing Fish Diseases and fish deaths; not something you want at any time!

A pond skimmer filter, in many instances also acts as a mechanical pre-filter that prevents large organic matter from entering and blocking your pond pump, pond biological filter or chemical filter. Some models are actually a biological pond filter system and skimmer filter in one convenient unit. Many models have rock effect lids so as to look like part of the pond layout or design.

Some models have been designed to be placed adjacent to the pond’s edge where they are easily disguised by plants and rocks. This type of pond surface skimmers also doubles up as a fancy and functional planter.

It is often a good idea when choosing a location to site the pond skimmer to place it near to a waterfall.

How does a pond surface skimmer filter work?

There are different models that have different functionality. As a rule however the following happens. As water flows around the pond it carries with it surface debris, including leaves which are sucked into the unit. In many ways it works in a similar way to a swimming pool filter. The pond water, leaves, twigs and other surface debris passes into a filter chamber where larger debris is trapped by a series of weir doors. Slightly smaller debris is trapped by a mesh net. The water, less debris then passes into the biological pond filter or is pumped back into the pond; depending upon the design of the system.

Smaller garden ponds often utilise what is known as a floating pond skimmer filter. The unit, as the name suggests floats on the pond surface and is connected to the suction inlet of a pond pump via some tubing (pond hose). The pump allows leaves and other organic surface debris to be sucked into the skimmer filter before the water, minus the trapped organic matter is pumped under force back into the pond.

Professional pond keepers and large fish pond owners; particularly those that keep Koi often use what is known as a protein skimmer filter. Unlike its mechanical skimmer filter cousins a protein skimmer actually uses biological processes to remove protein and metabolic waste products from the pond water; thereby helping to render the pond water safe for its inhabitants.

Remember that it is in fact a biological pond filter that removes ammonia and nitrites from the pond water. These toxic chemicals are lethal to pond fish, in high enough concentrations.