Hey Eric, I havent ran my bottom diffuser in a couple weeks now. The temp was getting way too high throughout. If I remember correctly, it was 90 on top and 86 on the bottom. Checking the temps just after the fountain shuts off still has a variance of only 7 degrees, but it opens up to 95 on top and 85 on the bottom by sunset.

I'm not able to get a DO reading, but with the temps being so close, I "think" I'm getting a pretty good mix.

.10 surface acre pond, 10.5 foot deep. SW LA. The epitome of a mutt pond. BG, LMB, GSF, RES, BH, Warmouth, Longear Sunfish, Gambusia,Mud Minnows, Crappie, and now shiners!!...I subscribe!!