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Influence of PP treatment on filter performance

A comprehensive study was conducted by Jasper Kuijper and Jan Stienstra on the use of Potassium Permanganate to treat filter media. The results are by now generally accepted throughout the aquaculture world. In essence, when filter material is treated with 6 g Potassium Permanganate per 180 litres of water, the surface area of the media is sterilized from harmful substances and the mould inhibitors on the media are removed. The main advantage is also that the Potassium treatment “prepares” the surface area of the media to facilitate faster biofilm maturity. The fact that this “preparation” of the media caused bitter arguments amongst the koi fraternity is now beside the point. What really fascinated me is some of the other findings that at first glance just did not make sense. The finding I am referring to is the positive impact of a Potassium Permanganate treatment on filter performance.

The treatment of brand new filter material with Potassium Permanganate causes the rapid development of a layer of organic macro molecules that act as a primer for bacteria to grow on. Without a Potassium Permanganate treatment this layer will take a long time (it will differ from pond to pond) to form and bacteria will find it difficult to establish. Now comes the interesting part. 

The study found that over time, the biofilm, especially in static media, will become thicker and thicker. The oxygen that will enter this layer through diffusion will be used by the outer layer of the biofilm and oxygen will eventually cease to reach the deeper layer of biofilm and that part will turn anaerobic.

The process is called Bio Fouling

The drawing below depicts the process. 


The impact will not be as severe in moving bed filters like Kalness because the biofim will be removed and renewed through constant friction. The problem with Kaldness is mainly that the protection offered to the biofilm on the inside of the spheres, will cause the same effect as in static media. 
The authors of the study results pointed out that in order to alleviate such problems, the advantages a potassium treatment of the biological filter should never be underestimated. The biofilm will not become thick enough to create anaerobic conditions and the Kalium that is a by-product of the treatment actually serves as a boost for the biofilter. 

Last Updated on Friday, 25 March 2011 23:03