I think for housing the Koi, a large show Vat maybe a good idea. They are available in all sorts of sizes and it's a good way of keeping most of the mature pond water too. You may be able to borrow one or get one second hand from ebay.
I take it with no bottom drain installed, you will need to take the filters down to plumb in the new pipework. What to do with the media in the meantime then.
How about getting some cheap PVC stackable containers to build a makeshift bakki shower? You could store the media in the bins, pump water from the Vat into the top tray and let the water pour back into the vat from the bottom. This should keep the water circulating, keep the media wet & well oxygoenated and serve as an effective inorganic filter too. Clarity won't be fantastic and daily vacumming of the vat would may be required unless you can turn over the contents realatively quickly, say every 45 minutes or so which is the optimum Bakki shower turnover rate.
The only other possibility and the best one of all if it can be done is to drain the existing filters, move them somewhere temporary and plumb in temporary supplies and returns from the vat. This will avoid disturbing the biofilm too much and keep ammonia & nitrite at zero.
Whatever you do, it will probably involve a pumped system with a gravity return so a low presure pump such as the Oase Aquamax would be better than a sequence which pulps up solid waste quite badly.
The above is based upon my existing plans to house my Koi when I re-design & Build my Koi pond next year.
Alan
Posted on Jun 21, 2005, 8:29 PM from IP address 213.120.101.21