This microprocessor-based pH indicator-controller provides a complete monitoring and recording system for industrial wastewater. Two process controllers are provided to activate alarms, pumps, etc., based on preset pH or millivolt set points. The unit can be mounted with 1/8 DIN or in a NEMA 4X enclosure. The recorder can be configured for either a 24-hour or seven-day chart with 0 to 14 pH. The system can be provided complete with probe and buffer solutions to calibrate.