"Pinkpggy" wrote in message
...

I will try and answer your questions. I am not sure how deep the gravel is
in
the pond. The top part of the waterfall is about 2 ft deep with gravel.
The
second section of the waterfall is not that deep.
The gravel in both the pond and the waterfall is river rock. We clean out
the
waterfall rocks every couple of months with a shop vac. We probably
wouldn't
need to, but I don't like the muck to build up. The drain is on the
outside
with a valve, we attach a hose to it and thats how we drain it. It works
very
similar to a under gravel filter in a fish tank. The undergravel filter
is
made of pvc pipe.

Hi,
I asked because I've worked with many sub-gravel ponds. I wanted to know if
there is anything new to keep this type of setup working indefinitely
because, IME, really cleaning them meant removing all the gravel and pipes.
Very few reinstall them. The problem is that sub-gravel filters act as
mechanical filters also and mechanical filters do not remove anything from
the pond, they only hold it in place until you remove it.
I was interested in the size of holes in the piping and the location of the
drain. You mentioned stuff floating after stirring the rocks so I was
confused with drain placement. I don't want to disparage you with this
setup, the good news is sub-gravel filters work great until they don't. Seen
some work for four or five years running 24/365 with a proper fish load.
L8R -_- how
no NEWS is good