Mechanical filters take solids out of a pond. They remove solids like fish waste, leaves, debris, sticks or any other rubbish that shouldn't be in a pond. They are usually the first step in a filter system. They remove anything that is too large to go into any other parts of the filter system. They are also good at keeping amphibians like frogs out of a pump! Mechanical filters are almost always required, unless you have an indoor pond or tank that isn't going to get anything in it that is going to clog a pump. Here's a couple examples of different types of mechanical filters:
Surface skimmers work by constantly creating a suction force at the surface of a pond. This force pulls any leaves, sticks, or un-eaten food into the skimmer. Skimmers usually have a net or a rigid leaf trap to capture all of the debris and Koi that wander in. There is also usually a filter pad behind the leaf trap, this helps with capturing algae and other solid wastes that pass through the leaf trap. The leaf trap should be emptied weekly. The filter pad should be sprayed with a hose at least once a week.
Bottom drains work by continually drawing water in from all directions. Bottom drains will remove any leaves, solid waste and small sticks from a pond that the skimmer missed. Koi produce a lot of waste and bottom drains are the only practical way to remove it. Usually, a bottom drain is piped into a vortex chamber.
Vortex chambers, which are fed from bottom drains, are a cylinder in which a large volume of water is circulating. The circulating water forces any debris like solid waste and leaves to the bottom, while the clean water goes into the intake near the center. At least once a week, the bottom of the vortex chamber should be flushed out to remove all of the settled waste.
Back to Pond Filters.