Today after 2 years and 132 days my water parameters are zero ammonia, zero nitrite and 7mg/l nitrate. All this with 50 large Koi being feed 450 grams of 43% protein food a day. Who says Anoxic filtration doesn’t work ?

This was posted on Koi 4 U  October 15, 2013 By: David.

So I thought it was time for another look at this thread & filter.  Over two years ago I decided to try out the Anoxic filter. At this time I was running a stainless steel EA system with an Answer fitted into the first tank and then Jap Mat in the second. With a pond of 45,000 lts and about 50 large Koi I was having difficulty with all the parameters. Next step was to try Kaldness K1, so I fitted a third tank and removed the Jap mat and purchased 350 lts of K1. Things did improve but I was unable to feed more e than 350 rams of 34% protein food a day. On top of this I had very high levels of nitrates through not changing enough water but I’m on a water meter and am paying 5 euro’s a cubic meter. Having also spent some time reading through Dr Novak’s PDFs I thought I’d give it a trial. This involved building a 3,000 lts filter to house the baskets. As it was a trial the filter was built indoors and is 1 meter lower than the pond so it also needed pumps and level switches. These of course need money and electricity but it’s only short term!! Finding the correct cat litter was a problem but after many trials with dissolving cat litter, I made 39 biocensis baskets and started the filter running. This improved the water parameters but very slowly as the K1 is producing nitrates at a fast rate. Over the next 3 months I removed the K1 at the rate of 5 litres a day.  So at last after 3 months I have a mature Anoxic filter but I have a pond full of hungry Koi and 45,000 lts of pond water with over 200 mg/l of nitrates! Time for the Anoxic filter to prove itself.  To help with the detritus problem I have removed the Answer and tanks and fitted a Cetus sieve. This is of course not perfect as it has a 300 micron screen and so some detritus still gets through. Because of the fast flow through the filter the waste tends to spread out across the floor of the filter. The detritus doesn’t go rotten and just seems to turn to “mulm” just like it does in a settlement chamber as used by some Koi keepers.  Today after 2 years and 132 days my water parameters are zero ammonia, zero nitrite and 7mg/l nitrate. All this with 50 large Koi being feed 450 grams of 43% protein food a day. Who says Anoxic filtration doesn’t work ? Plans for next year is to build a new filter outside next to the pond and replace all the pumps with an Airlift. Roll-on Spring time. Any questions ?

Rosewood Tetra Pond Floating Foodsticks, 450 g (1 lb), costing £9.28 a bag. That’s a lot of food a day and the AFS is handling it with no problems. 200-ppm of Nitrates is one of the highest levels of Nitrates I have seen/heard yet in a hobbyist pond and the AFS has taken that down to 7-ppm…WOW!