7. Model 5100: Verify that the barometer reading is correct. Calibrate the barometer, if necessary, as shown under 6. Dissolved Oxygen Calibration, Barometer.
Model 5000: Enter the current barometric pressure as shown under 6. Dissolved Oxygen Calibration, Barometer.
8. Make sure that the display readings are stable, then press the (AUTO CAL) soft-key to calibrate Dissolved Oxygen. The message "D.O. CALIBRATION SAVES" will be displayed for a few seconds.