"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.

One year I covered my pond and put in a small heater. Last year I put them
in a stock tank with light for the WH. Both worked out well, I had lost of
plants and fry with the stock tank. But the Stock Tank cost me about $20 a
month for light and caused a bit of excess moisture. I may go back to the
cover this year, but I haven't decided yet.

Cover was 2x4s insulated with Styrofoam and covered with OSB and plastic. I
also put a small heater in the pond to keep the water around 40°F. The big
problem was that the cover was HEAVY and difficult to put in place.