How to calibrate the ammonium sensor with the ammonium controller?

The Daruifuno ammonium sensor is used for measuring the water NH4-N value continuously. The sensor is digital with RS485 communication. When the users start to use the sensor, you need to perform the calibration. How to calibrate the sensor? Our DUC2-NH controller provide two point calibration. You can perform the calibration easily by the contrller. If you are interested in our ammonium analyzer, feel free to contact us.