esshup, at what depth are you thinking of doing temp readings? I have a maple syrup thermometer but cannot immerse it. I guess that means I could get temps down to about 8" deep.

This time of year we don't have hot days anymore so I probably don't need aeration at all.

Last time I did calculation of how much the air bubbles lifted water and how deep my system was and what its CFM of air was it came out that I was just about at turning over my whole pond in 24 or 26 hours if I recall correctly.

But even if I'm turning over the whole pond, I still notice that there is definitely colder water deeper than say 5 feet (just by how cold it is when wading in to do maintenance)