Regarding summertime...substantial aeration is necessary for my heavy fish load. But to the extent possible, I don't want to add heat to the pond and I don't want to exceed 85F through the depth. Ours gets a hard afternoon sun and develops a warm surface layer. I currently schedule aeration from about 10:30 pm (expecting the surface has cooled) to 10 am (about the time the sun illuminates the pond) and air is warming fast. With thermostat controls, I'd want the pond surface to have cooled to say, 85, so that surface water switch releases to the air temp switch which is looking for 85F air. The deep water sensor would not be controlling but just feeding to the data stream being recorded. With my shallow depth pond, seven feet, I don't try to maintain a thermocline.
