I mentioned in a post a while back that I wanted to cover off on a number of standard aquarium filter options that have been on the market for years and that may have a lot to offer the small scale aquaponics gardener.
As a general rule of thumb the greater the Biological Surface Area (BSA) the better (for more on this see here). Therefore, atleast a couple of the aquarium filter types discussed below, may be suitable options for boosting your biofiltration in a small scale aquaponics system.
Cannister filters are the most common filters used in aquarium set ups. They can be either external to the system or internal. They pull water from the fish tank and run it through a series of different filter media before the water is circulated back to the fish tank. These filters normally come with an inbuilt pump and serve as both mechanical and bio-filtration. They are easy to maintain and reasonably effective also.
Trickle filters pump water over number of perforated trays containing bio-filter material. The media is kept wet but not entirely submerged allowing for better aeration. The water is then returned to the fish tank. In standard flood and drain aquaponic systems the media in the grow bed is essentially playing this role.
Fluidized sand bed filters
The fluidized sand bed filter pushes water through a column of fine sand particles. The sand is brought into suspension allowing bacteria to colinize its every surface. This filter has me very intrigued. From the sounds of it there may be a number of minor maintenance obstacles to overcome before it can be used effectively in aquaponics but this type of filter has a seriously impressive surface area to volume ratio. Designing this type of filter into your system would allow for a very modest filter indeed.
Under gravel filter
Lastly there is the under gravel filter which is one of the earliest designs used for aquarium filtration. These filters are placed below the gravel inside of your fish tank and use airlift tubes to percolate water down through the gravel media. This type of bio filtration is reasonably inefficient and unlikely to be of too much use in aquaponics.
At this point I should probably admit that I have only trialed a couple of the aforementioned techniques but now that I better understand my options there will be no stemming my enthusiasm. I will be sure to keep you all updated on any future successes in this area.
Thanks for reading.