Hi,
You do have a "man made bio filter" it is the undergravel one. A problem,
IME, with this is that it is also the mechanical fiter. I have a few
questions on yours if you don't mind? How deep is the gravel, in the pond,
in the waterfalls? What kind of gravel is it I.E. crushed, river, large,
small, etc. ? How often do you have to 'shake up' this filter and after the
'stuff' floats to the top do you net it or does it go out a drain and where
is the drain? What kind of plumbing is under the gravel? What size are the
holes in the plumbing? How do you clean the holes?
L8R -_- how
no NEWS is good

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.









Jan
"Our Pond" Page
http://hometown.aol.com/pinkpggy/index.html