Troutgal, If you have the standard Koender 7 inch round airstone on your windmill this could be part of the problem, I realize that it may appear to be aerating things but you are probably less than .7-1 turn per day on your total water volume, no matter how much wind you have. 1-1.5 CFM through that stone at a 5 ft depth may move 150 -200 GPM at best which is not much vertical current.Large bubbles in shallow water will not circulate (aerate) Your DO in 75 degree F water should be 8.4 at sea level, figure 70-90 % is realistic and you see what your shotfall is. You could be turning 1300-1500 GPM at that depth 5ft, with the proper diffuser. Do some homework on diffusers and see if that does not solve most of the DO problems which in turn may solve the rest of the problems and symptoms.Good Luck Ted
