Hi, Have you converted the filter to hold the K1 or have you put it in a bag? If its in a bag this may be the problem if the K1 is not being circulated by the air. If not and the K1 is being aeriated sufficiently then id just start feeding your koi on a regular basis and cut down on water changes. 50L of K1 can handle 250grams of food a day, but only when fully matured, and it wont mature if the koi aren't being fed. It seems reverse logic and i had the same problem when i swapped to K1 but my levels were back to normal about a week or so after i started feeding the fish again. Keep an eye on the fish but your tank is lightly stocked so your fish should be fine. The ammonia should start to drop off soon and you will probably get an nitrite spike soon after but then this should drop off and your levels should be perfect.
Hope this helps.
Posted on Jul 12, 2007, 10:26 PM from IP address 82.38.193.186