Pre-filter, for coarse dirt

Good biological pond filtration always needs a mechanical pre-filter. This ensures that coarse dirt is removed from the water and does not clog the biological pond filter. This relieves the biological filter and allows it to keep your pond cleaner.

How does a pre-filter work?

A pre-filter is always placed first in the filter line and it has one purpose. To rid the pond of coarse debris before the water reaches the biological filter. Coarse debris must be removed from the water to prevent the entire pond filter from clogging up and suffocating the bacteria. The water-purifying bacteria need lots of oxygen to break down all the invisible waste, and a pre-filter helps with this.

You can also add a small air pump to your filter if desired. This will bring aeration to your filter, providing additional oxygen.

The vortex, sieve bend and drum filter

There are three types of pre-filters: the vortex, the sieve bend and the drum filter. A vortex is a kind of funnel. The pond water enters at the bottom and exits at the top. Because of its shape, it creates a vortex that causes the heavier particles to settle at the bottom. The vortex is very large and filters mainly coarse dirt. A sieve elbow is much smaller than a vortex and also better filters fine dirt particles. Because the sieve bend uses a very fine sieve, it does require a lot of maintenance. The drum filter actually filters all dirt and is fully automatic. It is just a lot more expensive and very large. Always check for yourself what kind of pre-filter you want.