Thank you for the guidance, fellas... I do sincerely appreciate it.
The answer to the question about the membrane diffusor location(s) is they are on the bottom at the deepest point (which is only about 7 feet).
The water temp was taken about a foot and a half below the surface. I just assumed that with all the circulation in the pond, the temp would be uniform within a few degrees. I can certainly check it deeper, farther from the sun so to speak.
Thanks again for taking a moment to respond and share some wisdom.
/c
