On Mon, 9 Jul 2007 08:25:14 CST, Derek Broughton
wrote:

Sure it's a lot, but it would make for a healthier pond. I'd disagree
with "minimum", though. Most ponders don't manage to change that much, and
most ponders don't have serious problems. I suspect that it depends
greatly on evaporation (Jan lives in the desert), and fish load.

I wasn't suggesting adding evaporation as part of the change out. Nor was I
talking regionally. I rarely give suggestions based on my location or my
situation. I was talking from the viewpoint of the KHA program and what is
currently considered best for koi, especially in a koi only pond.

IMO, even in a planted pond, if one is doing a lot of moving plants around,
in/out, dividing, adding new, etc. it is still good to remove 10-20%/week
just to get rid of some of the organics in the water given off by the
planting media. ~ jan
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Zone 7a, SE Washington State
Ponds: www.jjspond.us