Biofilters ... Importance of using the right filter media in fish pond filters
Biofilters summary
To summarize ... biofiltration capacity in any system can be enormously increased by replacing traditional plastic tubes by more efficient biomedia. Alfagrog is such a biomedia. Alfagrog is known as Supra in USA and can be bought here:
Alfagrog fantastic low cost biomedia ... buy here, search for SUPRA after clicking
Why? because it is extremely porous, full of tiny tubes if you like into which bacteria find their way and do their job. To keep the Alfagrog efficient it is best to keep as much solids as possible away from the surface. This is why cleaning the Alfagrog in a bucket of pond water now and again is recommended (make it easy by placing Alfagrog in string bag)
If you suspect that your filter is not working well enough then add a few litres of Alfagrog for a big improvement in biological and probably mechanical filtration. A single litre of Alfagrog will cater for a pond of 1,000 litres (about 240 US gallons) from a biological point of view.
| 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 |
The challenge in creating good effective bio filters is to get as much surface area inside your black box as you can. A secondary benefit of using Alfagrog is that the black box can be made smaller making it easier to install in the pond environment.
The important point to remember for the garden pond keeper is that it is NOT the size of the box that determines the capacity of a biofilter. The capacity is determined by the amount of biomedia surface area in the box.
In my opinion and also by independent testing the best run-of-the-mill garden pond filters contain Alfagrog. The best koi pond filters contain Japanese matting inside vortex filters for sound technical reasons to be discussed later.
The following points are important to consider when choosing a basic black box biofilter.
Good solids removal capability as evidenced in some pond filters by the use of open cell foam that fits into the chamber or box without leaving gaps around the edges.
Ideally there should be at least two layers of foams with different sized cells making the removal of solids progressively more efficient. The coarse foam should always be on top.
Water should ideally be distributed evenly onto the foam surfaces to get better distribution of water across the surface of the foams . Not easy to achieve in practice.
"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