Pond filters use bacteria to purify pond water
water, filter, pond, biofilter, bacteria, fish, solids, Alfagrog, litre, surface area, foam, waste products, filtration, plastic tubes, purify.
Summary:
One of the most fascinating parts of pond keeping for the enthusiast is the management of the pond water quality. This is where pond filters play a vital role.
This filter purifies the water and also does the secondary job of removing solids and particles that remain suspended in the water
That which is eaten by the fish is partly digested and partly expressed as a waste product, which sinks to the bottom of the pond.
At their simplest these biofilters are literally black or green boxes holding sponges, brushes or other means of trapping particles.
The boxes also contain plastic tubing often called Flocor, plastic balls, other weird plastic shapes or if you are lucky the boxes contain Alfagrog.
A biofilter first and foremost is designed to purify water and the secondary purpose is to remove the solids that make water cloudy.
Foam sheets by virtue of the many small holes in them also provide surface on which bacteria can grow as well as acting as a mechanical filter to remove solids.
By far the best means of getting large surface area into a small black box biofilter at low cost is to use porous ceramic materials like "Alfagrog". metres per litre depending upon the particle size compared to 0.2 square metres per litre for plastic tubes.