Have you checked your bottom temps after the pump shuts off? The closer the temp variance between top and bottom, the better idea you have about DO saturation at depth. It could be you can reduce run time even more if its equalizing temps faster. And with a good bloom to shade sunlight, it'll start cooling faster on the bottom and still have good DO.

.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!!