I seem to be the only one around who runs aerators all winter. I'm in Minnesota which is nothing like Manitoba but definitely colder than our friends in Texas. I believe my aerator has helped keep my fish going all winter because I'm not always able to keep snow off the pond. But I only run the aerator for two 4 hours shifts per day and I think the effect is more along the lines of keeping an area open so that the sun can get through more than adding air. It seems to be the consensus on this forum that if you can keep the snow off you don't need aeration. So far I haven't had the guts to turn my system off since my fish have done well for 3 years before anyone told me I shouldn't use it. My diffusers are also in the deepest water which I'm also told I shouldn't do. I will say in support of the idea that you don't need aeration is that I have a pond with two distinct sections (8 feet and 6 feet depths) separated by a long narrow channel. I have bottom diffusers in both sections but I only run the one in the deeper section during the winter because my family skates on the shallower section. So I plow the shallow section whenever I can. I discovered last year via fishing and with a underwater camera that my fish appear to all move to the shallower non-aerated section of my pond during the winter. I had thought it would be the opposite. So I believe that the aerated section may be getting too cold for the fish and the non-aerated section obviously has enough O2 in it because I've never lost any fish due to winter kill. So, all that said, I tend to believe you don't need to aerate if you keep the snow off but I still don't have the guts to turn mine off completely. I'm just going to keep doing the same thing that's worked. Signed, Still confused!

Gotta get back to fishin!