Q: What is a pond skimmer?
Skimming, whether you’re talking about ponds or not, is a method of filtration. Filtration is a method of removal. So when you hear about people in trouble because of skimming money it is not actually much of a play on words, they ARE skimming! And it will get you in trouble! The good news is that skimming ponds will earn you a reward! That’s what we want to talk about, pond skimming, because everyone likes to get a reward, especially pond owners!
Skimming your pond with a good quality pond skimmer is helping you with removal too, but it is removal of impurities from the surface of your pond. These “impurities” can be anything: leaves, pollen, seeds, grass clippings, insect larvae, floating algae. Of course all these materials are completely natural but in the context of pond water quality, these materials will eventually foul the water if not removed, and the most effective form of removal from a pond is skimming. Skimming can be achieved through various methods such as skimmer boxes, wet well skimming, negative edges, etc.
How does a pond skimmer work?
A good way to look at skimming your pond is as your “first line of defense” in your pond’s filtration system. I use the term filtration “system” because to effectively filter your pond you should have several types of filters working together to create a “system”. The pond skimmer should be just one component of your system. Your pond’s filter system should be designed so the “first line of defense” (or the “first pass”) of your filter system is your pond skimmer.
A pond skimmer is essentially a vault or a housing into which you draw your pond water. The skimmer uses a pump to draw water into the skimmer and this pump can sit directly in the skimmer or be installed exterior to the skimmer. The front of the skimmer has an opening cut into, it ideally about 8” across for a typical medium sized pond; although pond skimmers come in various sizes. Most skimmers come equipped with a small floating door called a weir. The weir may seem unimportant when putting together a pond skimmer because they are small,l however the weir is what creates surface tension, and surface tension is what effective pond skimming is all about! Without surface tension your skimmer box simply becomes a pump housing with only a minor degree of skimming ability. With the weir installed correctly the skimmer is now pulling off of your pond’s upper layer of water, the layer where all the materials fall and float before water logging and sinking to the bottom of your pond to sit and decay. Instead, the skimmer pulls those materials into your skimmer and gathers them in a net or mesh device allowing the water to be returned to the pond cleared of that debris. Many skimmers also allow for a sponge filter to be used as a “second pass” to filter fine particles from the water too giving nice clear particle-free water returned to the pond.
The pond skimmer does more than clear the surface of the pond. Pond skimmers increase oxygen levels in ponds helping to further purify the water, and of course provide rich oxygen for your koi and pond fish. Pond skimmers can do as much or more than any sort of submerged aerator, and they do not disturb the surface of the pond, allowing for nice visibility and reflections to be enjoyed from the surface of your pond.
Did you know that most oxygenation for ponds take place by way of the ponds surface area absorbing oxygen directly from the atmosphere. Those air pumps we use that create thousands of little bubbles that rush to the surface of the pond and explode really do very little to oxygenate. For oxygenation to occur those bubble need to have contact time with the pond water so they can give off the oxygen but they move so fast that there is really minor oxygenation that takes place. It is where the bubbles break up the surface of the water that the oxygenation takes place. Well a pond skimmer is constantly and rapidly breaking up the surface of the pond too. Pond skimmers oxygenate at a much greater pace, with more oxygen being absorbed into the water because the skimmer is constantly increasing the ponds surface area.
If you are not skimming your pond, or you are doing it the old fashioned way of passing the net through the water, instead of passing the water through the net; then you need to consider adding a skimmer to your pond to make your pond’s filtration system a more complete system. Pond skimmers greatly reduce the amount of pond maintenance you otherwise would need to do to keep your pond clean. The pond skimmer is easily one of, if not THE best piece of pond filtration that a pond owner should own!
Tim Trammell has been building, designing, servicing and maintaining pond in the Oklahoma City Metro area for over 20 years. His company Continental Ponds, is Oklahoma's first Master Certified Aquascape Contractor and is an national award winning pond and water feature builder.