Is it ok to leave the pump in the water for the winter as long as it
does not freeze?
I leave my waterfall pump running all winter. This ensures that thereis
always oxygenated water in the pond even if the entire surface iscovered in
ice

If you take your pump out for the winter ( which I don't recommend) you
must store it in water or the seals will dry out and it will be ruined. You
should not run your pump when it is cold enough to form ice on top....the pump
will pull the lowest layer of water....that is the warmest layer and it will
return much colder water to the pond. If you feel you MUST run it...then
raise the bottom of the pump at least 1 foot. The pump as I am sure you know
should never be sitting on the bottom anyway. Jerri

http://www.fringeweb.com/Ponds/JerrisPond