Residual analyzer is an analyzer, which is designed to continuously monitor free or total chlorine or other oxidants in drinking water, wastewater, cooling water and other process water applications. It has a unique 3-electrode measuring cell arrangement that enables it to measure in the parts per billion residual range, as well as high residual ranges to 60 mg/l. These are microprocessor-based and feature a large, dot matrix graphic display, on-screen instruction and automatic ranging.