One of the engineers at the YSI factory described a better technique for measuring DO or dissolved oxygen. He said the DO sensor is designed to measure a flow of water and compare the sample water against a calibrated fluid built into the sensor.
Several of our fellow stormwater colleagues tried this technique with good success. I made a short YouTube video that demonstrates the technique to induce flow over the DO sensor. Hopefully the short 2 minute movie provides sufficient clarity for this new technique.