A Hard Lesson to Learn
Over the past 8 months or so, I’ve had numerous problems with my Koi getting wounds on them (Peduncle, Nose & Mouth) that would not heal, even with Topical treatment and injections of Antibiotics (10% Baytril and Nuflor). Over time I’d also treated the Pond with Salt, PP, Virkon S and FMG (not all together, and with water changes before you ask!) but still my Koi went downhill.
My Pond parameters have been pretty steady throughout, but still my Koi picked up injuries, and many died despite my best efforts and help from other NWKS members. Scrapes from the affected Koi showed absolutely no parasites, and even the introduction of Heating in October did not seem to immediately abate the problem as I’d hoped.
Colin Jones, and then Greg Sutton from Richdon Koi Bulletin Board both suggested a high bacterial level in the pond may be aggravating other underlying problems (e.g. Over stocking, Introducing new Koi that had not been QT’d properly). The finger of suspicion turned to my Filters, particularly the Vegetable filter.
My Filter maintenance is pretty good, with regular flushing of the Bottom Drain and Vortex/Answer chamber. I also regularly flush the K1 chamber until the drain off runs clear. On Saturday 9th Feb I dismantled my K1 chamber, and to my horror found a layer of non moveable sludge in the bottom, under the perforated Stainless steel shelf. A possible hiding place for bacteria of the unwanted variety! I also stripped out the Vegetable filter, through which about 30% of the return water from my main filter passes.
After 2 years of running, the base of the 8 inches of gravel was “Rank”!!!! Anaerobic Heaven.
I’ve sketched below the original plan of the Vegetable filter, and the new lay out.
Original Layout of Vegetable Filter
Basically I’m reversing the flow, and also doing away with the Gravel in favour of a perforated plastic shelf. This will support my plant pots (Iris, Sedge grass, Marigold etc). The Jap Matting will also catch more solids that get through my main filter. This whole set up can be dismantled and cleaned with a Pond vac in minutes.
New Layout of Vegetable Filter
I’m also now lifting my underwater lights out of the pond and positioning them just above water level. My Venturi where warm water returns to the pond from the skimmer and Boiler /Heat Exchanger is now also out of the way of nosey Koi. With less protrusions and lower stocking levels, injuries should be minimised.
Hopefully, my remaining Koi will survive now. I’m trying Zinocef and topical treatment with Betadine where needed.
My pond problems seems to have crept up on me over several months. This made diagnosis even more tricky as you just can’t spot any trends. Assuming (and hoping) that I’ve started to crack the problem now, I’ll implement the following steps to prevent it happening again:
1. Lower stocking levels
2. Build a QT any quarantine all new additions
3. Avoid injuries to Koi with Underwater protrusions etc
4. Increase frequency of filter maintenance, especially the Vegetable filter
5. Install and extra air pump to increase the amount of air into my Pond and Filters and so reduce chances of dead spots and anaerobic activity.
6. Weekly addition of Magic Powder and Super C to improve water quality, clarity and Redox potential and reduce DOC.
7. Weekly use of Virusure to maintain lower levels of Bacteria and Viruses in the pond water
I hope this information is helpful to some of you,
Happy Koi keeping
Martin
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