CC - The late start of your aerator of 29 May, I think explains why the diffusers are not mixing real well below the 19 ft depth. As the summer and additonal aeration continues you should see a slow, gradual temperature increase at 21 ft. If you would have started you aerators sooner (late April) then complete mixing should occur at all depths when diffusers are located at 17ft with your current run times. Additional measurements, this year and next year, will tell the rest of the story. Keep us informed about your tests.
