This add-on valve assembly offers the operator a simple method of choosing between two on-board concentrate cells. The activation of the panelmounted switch routes the selected concentrate to the proportioner. The ultra-bright indicator lights provide visual confirmation of cell selection.

To assure accuracy, the patented main control module interface provides a calibration mode for each concentrate. The module also computes and displays performance data on each concentrate including: current water flow, total water used, total concentrate used and injection percentage. In addition, it warns the operator of low-tank conditions and simplifies operations by offering default injection percentages for each concentrate. When changing between cells, the system automatically runs a flush cycle to prevent cross-contamination.