Calictus koi pond filters
At the Swanley show there was an impressive display by Calictus Europe of their koi pond filters. They were showing off their latest range which includes the new Calictus Basic, a multi purpose pond filter that was released last month. This model lacks the features of the automatic version to be more affordable but can be easily upgraded later.
To those not familiar with the company, Calictus is from the Netherlands and has a good reputation with innovative designs that are gaining respect around the world. They have won several awards and their designs are all patented. The name Calictus comes from the Greek word for 'the clean one, the pure one' which fits rather well with the aims of a koi pond filter.
I've seen their filters before and I know of the brand but this was the first time I have investigated them close up. They are very well made and suprisingly compact for bead filters and being pump fed they can be positioned almost anywhere. The improvements in efficiency and size has meant they can fit even the smallest gardens when in the past koi pond filters were often a third or more the volume of the pond. It is recommended to use a settlement chamber like a vortex before the filter, and this would be necessary when using a gravity fed system by bottom drain. They work similarly to other bead filters with the small beads trapping the dirt and biologically breaking down the waste but where they differ is that the beads can be continuously aerated as in a moving bed and if required the filter can automatically clean itself.
It's this ease of maintenance that is very interesting for many people as even in the basic model without an automatic function, cleaning is as simple and quick as pulling a bath plug. The water and air pump agitated the dirt from the beads and the water is diverted to waste. The whole process takes less than 5 minutes and in the automatic models this can be set at different intervals. This means the filters won't get too dirty and clog up affecting the water quality. The problems with combining mechanical filtration with biological filtration is that often a compromise between the efficiencies of the two. Mechanical filtration gets better as it clogs up but this can reduce water flow, surface area and oxygen for the nitrifying bacteria. A fluid bed filter works well as a biological filter but has little use mechanically and even the constant banging together of the beads can be counterproductive.
This is where the Calictus has got it just right with the beads tightly packed to collect particles of waste and the time and oxygen to build an effective biofilm before the next cycle of cleaning. I think this is what the perfect koi filter should do, by continually removing waste from the system not just storing it away from the pond and decomposing it into other compounds. I don't believe there is such a thing as a perfect koi filter but in theory Calictus's range do seem the business. The only down sides are that they are fairly expensive but often in koi keeping the price for quality pays off in the long run.