Theo van Daele wrote:

The possible caveat with that is - as I sadly know from experience - if the
spilled water flows back *under* the liner (if you work with a liner) it
pushes the liner up which pushes the water up to reach the pump, flows back
under the liner... you get the idea I completely drained (no water left
at all , maybe 50 gallon) a 6000 gallon pond in about 7 hours ...

I was just lucky to have this happen before I put my fish back into the
pond.

I now have the pump 40 cm from the bottom, but with a very large rock (yes,
I know) underneath so that if the same ever happens again, the liner will
not just float on top but will be kept down (a bit).

I am currently looking for a switch that should stop the pumps when water
level drops say 15 inches.

I haven't seen them for sale as an add on: I bought my pump with one
fitted, like this one:

http://www.drapertools.com/draper/te...up=7058&g=4988

This means my pump can be at the lowest point on the pond and so manged
to suck up more of the grud that gets down there.

Thinking about it, I suppose you could rig up a float switch bought from
RS Components (http://rswww.com) or similar.


--
Matt Helliwell
www.helliwell.me.uk
matt at helliwell dot me dot uk