stacle was winterkill, every year. His original idea to aerate had a marginal impact because his natural pond has eons of organic accumulation.
https://fishing.qciss.net
The aeration of organic matter accelerates its decomposition, which burdens the water. It has a high oxygen demand, even with few fish.

I asked Patrick what would happen if Chad raised his diffusers halfway up during these cold months. He said, "If he raises his diffusers, the plume of bubbles will impact the water column at that depth and up."

To make sure I understood, I asked if the temperature of the water under the diffusers would be affected. He said that he would not.

He also says that the aeration system would move enough water into its effective zone that it would probably replenish enough oxygen for something to diffuse into a portion of that warmer layer below.

But, there's no way of knowing if he replenishes oxygen as fast as it could be used, that oxygen demand thing. Dissolved oxygen will migrate, but part of the mystery is how far that oxygen will move into that warmer lower layer.
Think of it this way. Spring