The CA610 is intended for use in finished drinking water, and in this application there are no real concerns with pH or other interferences. (Aluminum, however; is a known interference, and the analyzer allows user adjustment of the sample cycle to allow sufficient time for the TISAB reagent to mask this interference). The TISAB reagent was formulated to address the pH ranges and strengths that would be common to the drinking water application. The TISAB reagent itself has a pH of about 4.6. It is used to keep sample pH buffered to the acidic side in an effort to keep minerals in solution and prevent coating of the electrodes and to keep fluoride in the ionic state