Hi Tony- I think it can be helpful to share experiences and will add my winter aeration experience to expert advice by TG. I live about 70 miles to your NE. Our pond is about 1/4 s.a. and at least 35 years old. The deepest water is almost 10', but the "shallow" diffusers are in just 3' to 4' of water depth. (During the summer I operate a third diffuser in deepest water. I turn the water a lot in the summer, but I do that mostly because our pond was becoming eutrophic from leaves and organic waste- i.e. several inches of muck build-up.) I run a small, (80 LPM) linear diaphragm design compressor to push the air to the two shallow diffusers for the winter, 24/7. I began use of aeration the summer of 2019.

The first winter I ran the air at full flow from the compressor. This resulted in two fairly large openings in the ice that were sort of oval shaped and at least 15' in diameter. When ice out occurred I slowly lost about 20 bluegills and a bass. From what the county extension office shared and posts in this forum, I suspect that it was the red gill bacteria. Fish that were ill would swim slowly and seemed without directional control. Once the fish exhibited these behaviors, they typically died in a day or two. After some additional reading of articles here and in the PB magazine, I thought it was possible that I was turning the winter water TOO much, stressing the fish from causing even the deep water to become 34 or 35 degrees. So last winter I added a bypass valve at the pump in our shed that's 75' from the pond. I bypassed some airflow such that the bubbling at both diffusers looked more like an aquarium water filter bubbling. My goal was two openings no larger than 2' diameter. For last winter this reduced airflow reduced the ice openings to about 2' that I desired. More than enough to vent any bad gas and still allow some oxygen to mix into the water. And reduce the amount of cold water mixing during the winter cold. This past Spring I lost three or four BG and no LMB. Much better result. This small fishkill in Spring 2021 was more in line with what I have observed over the years. Most years maybe three or four fish die shortly after ice out and in some years none. I concluded that with similar minor fish loss this past spring as prior to using aeration, I may now have the aeration optimized for winter so added fish stress is minimal.

In the polar vortex winters of 2014 and 2015 we lost nearly all the fish in the pond. And those were the two winters with the coldest temps, thickest ice cover and no aeration. Maybe some of my experiences will help you. Admittedly I'm just 2.5 years into the use of aeration, but from what I'm observing, it has helped our pond.