as it hits as low as -40C here in the Toronto Area, I finally desided to
check on the pond for the first time this winter, I had built a teepee
style top over my small pond which at the centre is about 18inch high down
to about 8 inches around the sides, I have an air hose doing the bubbles
and I have covering over the whole top heavy liner, since it snowed, I have
about 6 inches of snow over the whole pond.

Today I dug out a portion of the liner where the airline is to see how much
of a hole has been kept open, and to my surprise, there is no ice on the
pond at all.

Last year I did the same thing but there wasnt any snow and I had ice about
6 inches thick.

Snow really works well as an insulator.

I recovered the liner with snow, my question is this

its pretty much an airtight lid over the pond, the bubbles are keeping the
surface of the water moving so the gases dont settles over the water, but
what about the airpocket I have created with the cover, is the gas
collecting in there, should I have some venting happening ? could I just
over the liner once in a while to put fresh air in there ?

Joel.