Shape of a biofilter does not matter. The biomedia inside does.
Once you fully understand what a pond filter does and how a biofilter works it is simple to buy the right pond filter and a basic biofilter will cost you very little. Even a very basic home made pond filter will make a dramatic difference to your pond's water quality and thus the health of the fish in your pond. It's not difficult to make your own pond filter
At their simplest pond filters or biofilters are literally black or green boxes square or round, fat and thin or whatever. Often they hold sponges, brushes or other means of trapping solid particles. The boxes also contain plastic tubing often called Flocor, plastic balls, other weird plastic shapes, lava rock, special tape, string bags and coke bottle tops. If you are lucky the boxes contain Alfagrog (called Supra in USA). The collective name for these objects is biomedia ie a medium (better still surface) on which biological activity can take place.
Biofilters always work best and your pond benefits most from combining the action of ultra violet light (UV which clarifies the water) with that of biofiltration ... in this way your pond ALWAYS stays clean and clear and healthy ... no more need to add anything at all to your pond water.
The picture below the table is of a brush that would often be used to trap solids in the circulating pond water.
| UV + Bio Pond Filter Selection Table ... By clicking the link below you can review a wide range of biofilters both with and without UV sterilizers. | ||
Fish-Mate Includes UV Sterilizer (see below ... if you're looking for a low cost well tested UV + filter combo for a small to medium fish pond this would be my recommendation) |
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| UV + Biofilter for ponds to 1,000 gallons | UV + Biofilter for ponds to 2,000 gallons | UV + Biofilter for ponds to 3,000 gallons |
| Combo UV + Biofilter for ponds to 4,000 gallons | UV + Biofilter for ponds to 5,000 gallons | UV + Biofilter for ponds to 6,000 gallons |
Here's a picture showing how such brushes might be arranged inside a box pond filter (sketch by Peter J May)
As often stated the specific purpose of biomedia inside all pond filters is to create surfaces on which specific bacteria can live in order to convert the waste products naturally and continuously produced in the pond to less polluting materials. The sponges and brushes are specifically there to play a role of removing some of the solids that get circulated through the pond filter via the pump.
A pond biofilter first and foremost is designed to purify water and the secondary purpose is to remove the solids that make water cloudy. Few people starting off with a pond realise this.
Buy low cost combo biofilters and UV units containing the best biomedia, Alfagrog, by clicking this image Combo filter & UV
"The Complete Pond Solver" by Tony Roocroft
2005 Edition. Essential reading for anybody who wants or has a garden pond. Get 12 Excel pond calculators free as well as "Water Lilies and Pond Aquatics" ebook also free
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