Ka30P wrote:

Energy usage is important. I think the least expensive way is to run a
bubbler but I could be wrong. Anyone know? We have some Canadians online
who can chime in with what they do.


I live in London (SW-Ontario) and my pond is about 1600 Gal. I just ran the
pump throughout winter (28 watt OSAE acquarius 660 GPH, so it was OK). This
kept an opening until Jan, but it froze solid during Jan and Feb. A slight
warm spell in march made the opening again. I had 3 koi (~8") and a few
gold fish. They all survived.

If you are really worried and is concerened about energy usage, try a small
transparent dome with a light bulb. This acts as a small greenhouse and
will keep an opening at a fraction of the cost of a pond heater.

Sam
--
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