Thanks for the awesome reply and information, very interesting. Just want to make sure I understand one thing. With the blizzard conditions we have experienced I am not yet able to get to my pond to turn off the aerator. Since it is frozen over and snow covered how concerned should I be about over-saturation of DO? Is there a point in time where it becomes an issue for fish? Should I get to it as soon as possible and turn off the aerator, and then look at drilling a couple holes in the ice, then turn it back on. I can drill holes right off the end of my dock, where I can check to keep them open.