Yes and No.
Yes - after cleaning you need to verify that the analyzer is reading correctly. The easiest way is to see how it reads when placed in 2 pH buffer soltuions. This is what you do when calibrating.
No - If the readings are within the specifications (+/- 0.01pH, +/- 1 mV for ORP) in the pH buffers a full calibration is not needed.
Another way to verify that the readings are correct is to take a process sample and accurately determing the pH or ORP value using another method. This may be a Handheld or Portable analyzer, or you may take a sample to the lab. Be aware that there are many processes that will read differently after the sample sits in a sample bottle for a period of time. For those samples the lab reading will be different from the On-line analyzer.
Buffer solutions are needed as an indispensable tool for maintaining an accurate pH measurement. Buffer solutions are used as references points for calibration and adjustment of pH measurements to compensate for aging and deterioration.
Liquid analyzers are used for monitoring process chemistry including water quality, providing process optimization and control.
pH electrodes and sensors are the sensing portions of a pH measurement. Various installation options including retractable, flow thru, immersion, and direct insertion. Proper pH electrode/sensor selection is critical for optimal measurement results.
Process analyzers are used to determine the chemical composition or physical properties of substances involved in industrial processes.