Ted - Since you have trouble regulating air to two diffusers at once, do you have a freeze control tank in your system? A freeze control tank or sediment bowl I think would eliminate this problem for you.
Water temp today was 47F. Aeration will stop this week. My compressor is cut back to one-half summer run times. I usually stop aeration when water temps drop below 48F. At that point the pond should be uniform temp and continual cooling will maintain destratification until freeze up in mid to late Dec.
