Composition, system, and method for treating water systems

A composition for treating a water system or membrane fluid system, such as a reverse osmosis system, to remove scale, microorganisms and biofilm, and corrosion by-products. The composition comprises chelating agents and a surfactant. The composition may be a solid dissolved by water or solvent in the system being treated or may be a pre-mixed foam or aerosol. A method for using such a treatment composition comprises contacting the treatment composition with substantially all parts of the water system and draining the treatment composition from the system before resuming normal operations. For certain systems, the method also comprises draining some existing water in the water system to remove prior treatment compositions and filling or rinsing the system with fresh water prior to adding the treatment composition.