My little 1/4 acre pond does not achieve a thermocline when I run the aeration at 2 turnovers a day even when the diffusers are set no more than 6 foot from the surface (currently one at 6', a second at 4", and the third at 3' - all in the dam half of the pond). The pond depth average is 6-7 foot deep with 30% of it at 10 foot deep. I suspect that achieving a thermocline with aeration requires a sizable pond with a rather flat bottom and high diffusers. My pond has very steep banks and must be conducive to full turn-overs even with high set diffusers. I do my best to control summertime temperatures by achieving a turn over or two at night, hence my need to oversize the system to get a turnover in a few hours for the worst of the summer. I might get a thermocline if I moved the diffusers much closer to the surface, but then I lose much of the water movement that I want for quick turnovers and I lose pond capacity. It's kind of a catch 22. I have stuck with full night time turnovers & no thermocline. No obvious fish kills with water temps in the low 80's, 18" down to the bottom during the heat of the summer. Part of me wants to turn the aeration off for the heat of the summer to see what happens with water temps...I just haven't been able to convince myself to take that risk.

Fish on!,
Noel