I've had my pond for 7 years now (Nova Scotia) and all I do is take out my
circulating pump and use an air pump with the hose threaded through a piece
of styrofome. The hose drops about 18 inches in my pond, the air bubbles
keeps the water aerated, and keeps a hole open all winter long. I've tried
to use an air stone, but it wasn't as effective as just the bare hose end. .
If there is a large snowfall, I just shovel it off around the hole so as to
be able to see the air bubbling through. Over the pump I just placed a
plastic coffee can so that the air intakes don't get plugged.



"sue" wrote in message
...
I live in Saskatchewan ,Canada and the winters are very cold here.I
mean -20 to -30 c on average .I have been putting my large koi inside in
the past but now they are too big.My pond is apr 600 -750 gal with 2 1/2
feet at the deepest and I would like to try a de icer.Anyone out there in
cold canada that has tried this please help,thanks.