The potential of membrane scaling control by a real-time optimization algorithm was investigated. The effect of antiscalant dosing was evaluated from the induction time measured in glass batch-reactors, and operational performance of a lab-scale reverse osmosis (RO) unit and two pilot-scale RO units. Step changes in the antiscalant dosing demonstrated that that the accumulation of scaling is ‘paused’ during periods with the correct dosing. This is paramount for the application of a dynamic dosing strategy that may briefly underdose, while searching for the correct dose. It was found that antiscalant underdose and overdose were both detrimental to the RO operation since underdose resulted in membrane scaling, while overdose led to membrane fouling due to calcium-antiscalant deposits. The dosing algorithm was used to control the dosing of two RO pilot units. The algorithm identified minimal antiscalant doses and reduced antiscalant consumption by up to 85–90% for the plants mentioned.