I agree with DNickolaus, that under aerating could create a lower water quality in the whole pond than if the pond was not aerated at all.
Do you think I could be doing this Esshup?
Possibly. Read what Bill Cody posted above. Since the single aeration windmill last year was not enough to open a hole in the ice and keep it open, this year I would try to get a hole open and keep it open. I think by having a hole open it will greatly help in your situation.
With not having anyone on-site during the winter, and the altitude that the pond is at, you have a uniquely difficult situation.
Without on-site monitoring, you don't know if it is a problem of the line freezing up and not getting air to the diffusers, air getting to the diffusers and just not being able to open the ice in a large enough area that it also melts the snow which stays bridged over across the hole, or not enough air getting to the diffusers to have them move enough water to punch through the ice.
I know your airline isn't this size, but I have seen grid based compressors have a 3/8" like freeze up, even when operated 24/7. With alcohol injected into the line, the plug thawed and air to the pond was restored. An automatic system like that would help if that was the problem.
