Ok I recalibrated the meter for the 3rd time, replaced the membrane and used zero oxygen calibration solution. The meter still seemed to think it is dead on, very slight if any adjust was required. I might rent a YSI meter tonight to see if it shows anything different. Below are the readings from last night at 8:30pm and this morning at 6:30pm. My readings in the early evening are still show above the maximum saturation levels discussed above which is driving me nuts...
Updated DO reading from
8:30pm 7/23 and 6:30am 7/24
Near Surface Aerator
8:30pm 6:30AM
12" 9.2 7.0
24" 8.9 6.5
60" 8.4 6.3
Dam
8:30pm 6:30AM
12" 14.5 6.4
24" 11.0 6.3
60" 5.0 4.5
Middle
8:30pm 6:30AM
12" 13.3 6.6
24" 13.0 6.3
60" 4.0 5.7
I guess if these readings are not possible based on the maximum DO saturation maybe I have a bad meter...
