Mechanical filtration can be accomplished in many different ways. The job of this filter is to trap solids, preventing them from clogging the Biological filter. The mechanical filter should be backwashed or cleaned out often. Types of mechanical filters include Vortex, brushes, matting, sand and gravel, sieve screen, and settlement chamber.
Biological filter
Biological filters convert the nitrogenous wastes from the fish. This cycle is called the nitrogen cycle. A biofilter can be constructed in many different ways. It is important for the koi keeper to understand how the filter is to be cleaned before they install one. Proper and regular cleaning of the mechanical and biological filters is critical for the health and quality of the koi. Bio-filters are sometimes divided into sub groups such as aerated or non-aerated. Types of bio-filters include:
Trickle Towers
First developed by the Momotaro Japanese Koi farm, the bakki shower attempts to simulate natures way of filtering water. Similar to a mountain stream where water cascades over rocks.
Biofilms and algae grow on the rocks and feed on the nutrients in the stream, essentially filtering the water. In the case of the Bakki shower, ceramic is placed in trays and the water pumped to the top of the filter and trickles through the media, eventually flowing back to the pond.
Sieves and micro bead filters
These filters are still very popular and they work really good together mainly on a gravity system fed by a four inch bottom drain,the sieve will take out all the large waste including blanket weed,the pump will pull the water from the sieve,take it through the micro bead filter that will polish the water quality then it will go through the ultra violet system on your pond and then returns to the pond either by a trickle tower or water fall or return pipe.