Calibration of conductivity is not required for this unit as it is factory calibrated. However; if you wish to calibrate the unit follow the instructions below.
YOU MUST CLEAN THE PROBE BEFORE CALIBRATING.
You will need 2.77 EC calibration solution.
In the App, go to Settings > Configure Modules > (Module Name) > Reservoir TDS > Calibrate.
Once you are on the Calibration screen have your probe in open air. The App will display the "Measured 1" underneath "Solution 1" and will fluctuate for several seconds. When the reading appears to be stable, choose "Continue." (It should stabilize in less than a 30 seconds.)
Next, place the probe in your 2.77 EC calibration solution. Again, the "Measured 2" value (voltage) will appear and fluctuate for a moment. When it has stabilized again, choose "Continue."
Your TDS sensor is now calibrated.