This sounds like a workable solution for the rock bottom ponds. It would
work much more like the undergravel filters of aquariums since you would be
pulling water through and then filtering, etc. One caution would be to put
sufficient support under the grates to be able to walk on the rocks.You
never know when you will have to get in to rearrange pots, catch fish, etc.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"Courageous" wrote in message
...

We are with the no rocks cohort. They don't give you all that much
surface as compared to plant roots. Easy clean bottom is overwhelmingly
best.

As an aside, my pond build will featuring a sort of false bottom;
think egg crates (small pallets really) raised off the bottom, with
small flat stones on top of them to hide the egg crates. This is
because I want to create a hiding place for certain species that
are shy. The design features the bottom drain pulling from under
the rocks; my theory here is that small bits of detritus will be
pulled to the settling tank.

I really have no idea how it will work out. Just this whacky idea
I have. Note how if it doesn't work out, the whole thing can just
be removed. I then I have a flat bottomed pond.

C//