In the situation that your Go Direct^® Optical Dissolved Oxygen Probe (GDX-ODO) stops reading any values and just reads 0 mg/L, first try going through the calibration procedure to reset the sensor.

To do a reset, follow the instructions below.

1. Fill the storage bottle to the top of the sponge with distilled water.
2. Insert the probe into the storage bottle and make sure it is positioned vertically so that the tip is not in contact with the sponge or water.
3. Start the software and identify your probe, if necessary.
4. Keep the probe in a vertical position for a minimum of 60 seconds.
5. Click or tap the sensor meter for the channel you want to reset (DO Concentration or DO Saturation).
6. Choose calibrate, and follow the instructions on the screen.

If resetting the calibration does not contact Vernier Support at support@vernier.com or 1-888-837-6437 for a return merchandise authorization for your sensor to be evaluated.