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 screens, and settlement chambers.

Trickle Towers First developed by the Momotaro Japanese Koi farm, the bakki shower attempts to simulate nature's 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 is 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 well 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, and 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 ultraviolet system on your pond and then returns to the pond either by a trickle tower or waterfall or return pipe.

Drum Filters have made a big impact on the koi scene in the past few years, Oase drum filters are the ones that stand out by a mile in my opinion.