HACH CL17 Free Chlorine Analyzer is a cost effective instrument to measure free chlorine in water continuously and requires low mainten ance. The measuring range goes from 0 to 5 mg/l and it provides a continuous analog signal which is proportional to the chlorine concentration of the sample. every 2.5 minutes a complete measuring cycle is carried out. the conception of the instrument allows an unattended operation during 30 days.