Abstract: A sample coupon of known dimensions is immersed in the electroless plating bath. Immersion time can extend for the life of the bath. The coupon is attached to a load-cell which incorporates strain-gauge technology. The millivolt output of the load-cell to galvanometer displays weight gain at chosen intervals (e.g., 1 minute), and can signal operator if weight gain is less than the chart contained in engineering specifications to make replenishment additions defined in specification. The galvanometer output, with specialized software to computer traces weight gain profile providing data for actuating valves (e.g., proportionating pump) and provides hard-copy quality control record. Control of this one chemical replenishment parameter is sufficient to give real time process optimization and minimizes auto-catalytic breakdown. Instruments can be positioned in controlled environment.