1/ A pump that sits on the bottom of the pond and pipes going upto a filer
and returns back.

2/ Or a pump that sits in a pump house out side the pond and pipes run from
the pond through the pump then into a filter & uv light & back to the pond.
Mostyn

#1 works for a small, light stocked water garden, BV mentioned the
potential problem of draining the pond. There are automatic shut offs
available. (Mercury Flow Switches)

#2 is better for bigger system, but still not ideal, imo. Better is to have
the pump after the filter, less wear and tear on the pump and muck isn't
ground up into tiny bits that can by-pass the filter.

As far as pumps, external pumps are more efficient as they give more gph
using less energy, but a submersible can still be used in an out-of-pond
filtration unit. I have this type of system diagrammed on my website, with
plumbing added after the pond was been in and plumbing correctly when put
in at the same time as the pond. See *My Filter* *Demon Pond Filter* &
*Lily Pond* with the last set showing what the plumbing looks like under
the pond. There are of course all sorts of variations.

My lily pond at this time has set up #1 until we put in (read: have money)
the out of pond filter & pump. ~ jan
~Power to the Porg, Flow On!~