Our lake corporation bought a Sentry 3 oxygen meter a few years ago and we have been real satisfied with it. It not only checks the oxygen but the temperature of the lake. I check the lake temperature and oxygen once a month at surface, five, ten, fifteen, twenty feet and the bottom at seven different locations around the lake and keep records of it. We do this to monitor the progress of the eight diffusers in the lake. We have found that with the diffusers going the lake temperature is within about three degrees from top to bottom. It also helps us to figure out how much chemicals we should put in the lake to not deplete the oxygen.
