The CL17 analysis method is not affected by changes in chlorine concentration, sample pH, temperature, flow or pressure, thus offering more reliable and accurate measurement with less operator interventions than other methods in today’s market. Monthly routine maintenance for the CL17 can usually be performed in 15 minutes, including changing reagents and cleaning the colorimetric cell. No special tools are required. For typical use, the CL17 will operate unattended for 30 days. The CL17 is also suitable for permanganate residual measurements. Laboratory and field studies demonstrate the analytical capabilities of the analyser to determine permanganate concentration in water and confirm that it is a robust solution and a good tool for the control of challenging water treatment processes (variable water quality and demand).