Color together with odor, taste and turbidity form an integral part of our sensory system. The term "color" is normally used to indicate "true" color, i.e. the color of water from which turbidity has been removed. The term "apparent color" refers to color due to both substances in solutions and suspended matter. Apparent color is obtained without filtering the original sample. Color in water is due to natural ions such as iron and manganese as well as plankton, humus and peat materials. Industrial waste, especially from textile, paper and pulp processes can also contribute to presence of color. A colored water is also a result of agricultural pollution.The HANNA® solution is a microprocessor-based meter that measures both true and apparent color of minerals and natural constituents in water from 0 to 500 PCU. The microprocessor driven HI 93727 guarantees precision for every measurement.The HANNA® HI 93727 Color meter uses the Platinum Cobalt method considered to be the standard method of measuring Color in drinking and natural waters.Results are expressed in digital readouts saving you from complicated comparison procedures to determine the color.Range: 0 to 500 PCU (Platinum Cobalt Units)Resolution: 10 PCUAccuracy: ±10 PCU ±5% of readingLight Source: LED 470 nmLight Life: Life of the instrumentLight Detection: Silicon PhotocellBattery Type / Life: 1 x 9V / approx. 40 hours of continuous use; auto-off after 10 minutes of non useEnvironment: 0 to 50°C (32 to 122°F); RH max 95% non-condensingDimensions: 180 x 83 x 46 mm (7.1 x 3.3 x 1.8")Weight: 290 g (10 oz.)Method: Colorimetric Platinum Cobalt Units