There are many and varied forms of filtration, mechanical filtration, biological filtration & chemical filtration.

Most types of filters will use mechanical filtration along side biological filtration whether it be a bay filter/black box filter/nexus, Sieve/Drum & bead filter etc.

Pre-filtration of pond water via a vortex or sieve is recommended to remove larger particles of waste most pre- filters dump waste water directly to a  drain or soak away saving load on the biological side of the filter .

Here at Angelkoi we can source pretty much any type or style of filtration to suit any project/pond.  We also work closely with local fibreglassing company who manufacture Bakki Showers, Multibays and Vortex type filters to measure.  please contact us direct with any questions