Russ, thanks. Good question on aerating 24/7. I gave this a lot of thought, read PB forums, and asked questions to the hy-on-a-hill trout farm in Plainfield, NH from where I bought the trout.
I did not aerate 24/7 in the hottest part of summer - when bottom water temps got above 65 deg f. I had a timer that only aerated from 2 to 6 am. The thinking was that aerating (and the consequent circulation) during the hot days of summer actually increases water column temps, by preventing the natural effect of thermal layering. But that the nightly drop off in dissolved O2 is countered by the aeration during early morning hours. Starting to aerate at 2am gave time for surface temps to cool before mixing the water column.
It seemed to work... Although I've got 25 brookies that are definitely AWOL. The rainbows definitely did ok, but they were completely dormant(at least not observable activity) during hottest parts of summer.
During spring & fall I aerated pretty aggressively - but would time it to stop during hand-feeding so the pellets would not wash to the side of the pond. Aeration stopped before ice-in of December. Informed by PB, I chose to not aerate during winter. The only concern being that more than 24" of snow cover on ice may prevent light penetration and lead to critical drop in dissolved O2. But that did not happen here in NH.
