These temps were taken 12 hours after aeration was turned off. - giving it time to stratify a little??? I am going to bet that the temps are very consistent below the 36" to the bottom. I will look over the pump this weekend while running, but I think all is good with the pump. It's not uncommon for my pond to have a good delta T between the very surface and a foot or so down, long after the air turns off. The water temps have been very consistent from top to bottom at the end of the air run-time, indicating good turn overs.
IIRC your pond is deeper than mine. Mine is 10 foot and your water is much more clear. Does muddy water heat up more at the surface??? My pond also receives very little wind action. I'm just thinking of the differences that may come into play.
Keep an eye on me Augie! I will get more temps checks and such this weekend and maybe it will paint a more thorough picture.
