The use of a Chlorine Dioxide Test Strip can provide fast and reliable monitoring of chlorine dioxide levels, including residuals. The High Level Chlorine Dioxide Test Strips detect levels from 0-500ppm in increments of 0, 10, 25, 50, 100, 250, and 500. Chlorine dioxide has a higher oxidation capacity than chlorine or ozone, which means lower concentrations of chlorine dioxide can be used to achieve effective disinfection. It can also be used when large amounts of organic matter are present.