Years ago I bought a temperature/visibility probe to use for bass fishing. I recall it had some type of dissolved oxygen readout on it. However, the probe was completely encased and didn't actually sample the water. It based its DO reading on assumptions (temperature, barometric pressure, etc) and didn't actually test the water for DO. I'm pretty sure the model I bought was similar to
this one. Keep in mind this was more than 15 years ago and my mind ain't as sharp as it used to be.... not that it was sharp then.
