Use overview： This instrument uses photoelectric colorimetric detection principle, instead of the traditional visual colorimetric method. It eliminates the man-made error and has higher measurement resolution. The water sample will change rapidly when the ion in the water reacts with a specific reagent. The water sample is then placed in the photoelectric comparator of the instrument, and the instrument will compare the color depth to obtain the concentration of the corresponding ion. The utility model can be widely applied to the inspection departments of water works, industrial and mining enterprises, hospitals, living or industrial water, etc., so as to control the concentration of ions in water and reach the required water quality standards. This instrument conforms to "GBT5750-2006 drinking water standard examination method" national standard Determination method.