Water Quality Analyzers

Water quality analyzers measure pH, ORP, residual chlorine, conductivity, turbidity, dissolved oxygen and other parameters, either as portable meters or as online instruments. This section focuses on online analyzers: a sensor (electrode) plus a transmitter or controller with 4–20 mA, relay or RS485/Modbus outputs that connect to a PLC or drive a dosing pump directly for closed-loop control.

Typical uses include residual chlorine monitoring in drinking water plants and secondary supply, pH neutralisation in wastewater treatment, conductivity monitoring of cooling and boiler water, and chlorine and pH control in swimming pools.

When selecting, check measuring range, process temperature and pressure, installation style (insertion, flow-through or immersion), temperature compensation, and how often the sensor must be cleaned and calibrated. Electrodes are consumables and should be calibrated and replaced according to the duty.