Derek Broughton wrote:

Care to take a survey? From many years on this group, I can assure you that
most of the regulars here do _not_ have rocks or gravel on the bottom.
Most of the people who ever did, rip it out.

I took the gravel out of my pond only last week. I left a very small
amount in just to amuse the fish with something to mouth at and in the
process help swirl the bottom. This morning the water has never looked
clearer, the muck is now going to the filter where it's supposed to be
and not trapped in the gravel.

--
Andy