Abstract: A pump monitoring and flow control system that provides direct indication and control of discharge flow on gas driven positive displacement or diaphragm injection-type pumps. The device uses a “tell-tale” check valve that drives a proximity switch each time the tell-tale valve, installed as the output check valve on a standard injection pump, opens with discharge flow. The proximity switch in turn signals the monitoring system which computes the volume of chemical injected and controls the injection pump gas motor to provide the required volume of injected fluid. Additionally the system can alarm if injection flow is interrupted.