IQCL Smart Water Chlorine Sensor Modbus RS485, 5m cableIQCL Smart Water Chlorine Sensor Modbus RS485, 5m cable Residual chlorine refers to the amount of chlorine left after the effective chlorine has been in contact with water for a certain period of time after adding chlorine for disinfection during the water treatment process. In addition to the amount of chlorine consumed by the bacteria, microorganisms, organic matter, inorganic matter, etc. in the water, this amount of chlorine is called residual