Inlined Chlorine Sensor for water quality monitoring

The management and use of water require quality control to ensure integrity and assurance of water quality. The use of disinfectant agents, such as chlorine, to minimise microbial contamination is common practice and requires specialised sensor probes to ensure adequate concentrations are present or absent where downstream processes are chlorine sensitive. I would like to know what inlined chorine sensors you are using in water resource management? If you have any white papers for different make of chlorine sensor, please share them and your recommendations and experiences.