If you install a veggie filter a partial water change is necessary only once a year
or so. arggghhh... dont use pea gravel. The best biomedia is nylon screening,
reticulated foam, and polyester batting. Ingrid

On Mon, 7 Apr 2008 21:44:29 EDT, Peter Pan wrote:
Jan I've been looking at them and yes I am considering them. The
question I have about koi, according to what I am reading, they require
a cleaner environment then gold fish. I'm wondering with 3200 gal, how
often will I need to perform a partial water change?
The other question is, what do I use for a substrate? I was thinking Pea
Stones (pebbles)