The CD-2000 measures the amount of chlorine consumed by ammonia, iron, manganese, and other organic materials and provides advance information as “Chlorine Demand” in raw water. A corresponding amount of chlorine is added for clean water with a consistent level of residual chlorine. The unit may be used for daily control and research purposes. The instrument measures chlorine demand in drinking water, waste water, rivers, lakes, dams, wells, and sea water quickly. Reportedly, it delivers accurate measurements without interference by turbidity or color of the water and allows determination of volume of chlorine to be added. Correct volume of chlorine can be determined in advance.