I would also assume that the temps would be consistent throughout the water column, my question is...is 82 degrees too warm?
And, can your diffusers be set higher in the water column so that there is a thermocline that allows for a cooler water reprieve? I doubt that is really possible in such a small pond with that size of an aerator system. Only running the aerator at night could keep the pond's temps lower and your air system is certainly large enough that it does not need to run 24/7.
I'm looking forward to some expert details here, I'll keep tuned as I will be aerating this summer and could use some more lessons.