Theo, I started off with a nice little 100 gal. preform, into the bottom of
which I poured 1" gravel to the 2" mark. Two months later, I installed my
1200 gal. pond. When I removed the rocks from the 100 gal., the smell was
enough to gag a maggot! And that was only after 2 months, with a lot of
plants and 3 little fish! Needless to say, the larger pond, and the tank I'm
building in the back yard, are rockless.

Rocks are fine for watergardens, but are NOT suited for places where there
are animals. The only way I can endorse a rock bottom would be if very large
rocks were used, and they were mortared to the bottom/sides. That would not
allow the accumulation of the gunk (as readily, at least). However, after a
few months, everything gets covered in algae anyway, and you can't see
them - so why bother?

Lee

"Theo van Daele" wrote in message
...
Hi folks,

I've been an irregular customer here since 1999, not posted much, so my
word
will not really mean much.

That said...

*Don't* put any substrate or lave stones into your pond when you have
fish/koi.

I cleaned out my pond today (digging a bigger one) and I was honestly
disgusted with the lava/poo mixture I found in there. Sure, I only had 3
pumps going 24/7 doing 30.000 litres an hour, but still... utterly
repulsive.

Nothing new, most koi sites seem to agree, but I've seen it with my own
nose... horrid smell, disgusting.

Just don't do it :-) A bottom drain might be wiser.

Theo

PS: pictures of pond extension will follow, for old shape, click
http://www.wide-o.net/pond2003/index.html