Noel, thanks for the additional data points on water temperatures! (They are helpful because I think my latitude is just a little south of yours.)


You have said twice in this thread that you leave your aeration on for better DO. However, the "dissolved" portion of the oxygen in DO is strongly temperature dependent.

[Linked Image from palax.tk]

Pumping more air bubbles through a column of oxygen-saturated water DOES NOT provide any more usable oxygen to the fish. Further, to the degree that your aeration increases your pond temperatures (it does), then it will actually decrease the usable oxygen to the fish as your temperature increases.

I could give a long thermodynamics explanation, but hopefully one of our aeration experts can explain it more clearly and succinctly.