A chemical dispensing system includes a system controller, machine interface, and pump controller that communicate through serial data buses. The system controller provides a user interface, retrieves washing machine status information from the machine interface, and issues product dispensing commands to the pump controller. The pump controller monitors pump status and dispenses product in response to commands from the system controller. The pump controller: (1) determines pump activation periods based on calibration data stored in a pump controller memory; (2) tracks pump usage and adjusts the activation period to compensate for pump wear as the pump ages; (3) disables the pump if conditions exists that preclude operating the pump; (4) monitors product levels, and (5) reports pump status to the system controller. Integral channels are included in the pump housing to provide stress relief to a squeeze tube.