HJ 926-2017 "Technical requirements and detection methods for mercury water quality automatic online monitors" specify the technical requirements, performance indicators and detection methods of mercury water quality automatic online monitors. This standard applies to the production design, application selection and performance testing of mercury water quality automatic online monitors. According to the needs of different monitoring occasions, the range range of Type I and Type II instruments is specified respectively: Type I is suitable for surface water, groundwater and drinking water, etc., with a range of 0~ 0.002mg/L; Type II is suitable for domestic sewage and industrial wastewater, etc., with a range of 0~ 0.1mg/L. The standard refers to GB 4208, GB/T 12519, HJ 212 and other related documents to ensure the Reliability and accuracy of the instrument in various environments.