A dynamic simulator for pH control studies is offered. The process influent is composed of Various mono- and di-valent acids, bases and common ion salts and is treated with a multi-component reagent (either acidic or basic). Mixing is in a nonideal continuous flow stirred tank. Dynamic behavior includes : sensor lag; measurement noise; and autoregressive drifts on influent composition, flowrate and sensor calibration. Idealizations in the model were intentionally chosen to balance computational effort with output accuracy. The program output is shown to duplicate a wide range of pH results and to be sufficiently accurate for use as a dynamic process simulator for process control studies.