"FBCS" writes:

I awoke this morning and as every morning I went outside for a quick trip to
the pond to feed the fish while coffee is making. To my horror not the usual
nice sounds of water running down the falls, but the gurgling of a submersed
pump in an just about empty pond. Fortunately there was about 3" of water
left for the fish. I filled it back up and the fish are doing fine. Even
with all this new water I still have murky water.

Good reason not to have the pump on the bottom. Similar downside with
bottom fed bottom drains. Hope everyone survives.