Southern Water has developed enhanced chemical dosing control to optimise the application of ferric and caustic across a range of wastewater treatment processes. The implementation of this dosing control has stabilised phosphorus removal, protected iron permit, maintained sufficient alkalinity for nitrification, and minimised chemical consumption under tightening permit conditions. The development of these dosing strategies began in earlier AMP cycles and was modified significantly in AMP6 and AMP7 to cater for two-point ferric dosing control to achieve low phosphorus permits and therefore requiring efficient caustic dosing system to maintain sufficient alkalinity. All these modifications were based on full‑scale site experience and operational feedback. Sites requiring multiple dosing points for ferric and alkalinity, the intelligent dosing control integrates real‑time online monitoring and provide robust feedback control loops. All this gets optimised under varying influent and process conditions, including high flows / storm conditions to ensure good performance. There are five ferric and caustic dosing control modes, all of them with a back-up mode in the event of failure. The control system has the flexibility to cap, inhibit, increase or decrease the chemical dosing under various operating conditions. If the dosing system detects a failed or out of range instrument, control system has the flexibility to overcome that scenario without affecting site performance and chemical dosing. Implementation of the intelligent control philosophy has delivered improved stability in phosphorus residuals, reduced caustic consumption, and greater resilience during periods of variable flows and loads. All this have been central to managing low phosphorus permits on sites with limited alkalinity and nitrification requirements. The presentation will outline the development of the control logic, the operational lessons learned during optimisation, and the long‑term opportunity to reduce chemical usage (potentially by more than 50%) while maintaining robust and compliant treatment performance.