For a southern pond: I use my aerators in part to control the pond temperature, timing for night in the summer and daytime in the winter. If a blue norther is blowing in at 2 pm, the aerator runs per its timer or until I turn it off. I just got this idea that a thermostat controlled switch would allow automatic operation. Even better, a delta T controlled switch, set for air temp versus water temp. In winter, run for air minus water = 5 degrees or more. In the summer, the delta T may not be useful, but using just an air temp switch, say set to cut in at 84F, the night time aeration is optimized. A separate switch based on surface water temperature could be effective, for example not allowing the run until the surface water is cooled off to 85F. Well golly, now my "thermostat switch" needs multiple temperature inputs to a little "pi" computer, that outputs on or off, dials and data recorders for monitoring actual temperatures (a phone app for same, lol), multiple setpoint knobs, two waterproof sensors with long wires, and a weatherproof box.