Data from simulation studies of the hydrogen peroxide-sodium thiosulphate and hydrogen peroxide-potassium dichromate reactions were employed to select experimental parameters for the study of metastable states in stirred reactors using microprocessor control. The peroxide-thiosulphate system was found to closely approximate the simulation results and microprocessor control within the metastable region was achieved using a simple proportional+integral (PI) control algorithm. With the peroxide-chromate reaction, existing kinetic data had to be corrected for pH effects to enable accurate simulation. The existence of metastable states in this system was demonstrated experimentally, and microprocessor control within the metastable region was again possible using the same PI control algorithm.