The easy-to-use and economical CA6 colorimetric analyzer provides accurate measurement of manganese or iron levels in municipal drinking water production, food/beverage processing and other high-purity water processes. It is an online sequential sampling analyzer. A sequence of sampling, analysis and results processing is performed and repeated using colorimetric methods. This technology relies on an LED light source and a heated colorimetric cell designed for measuring trace amounts of manganese, iron and other analytes in water.