Abstract: An electronic control initiates and controls the regeneration sequence in a resin-type ion exchange apparatus of the type requiring periodic resin regeneration. The electronic control controls the regeneration steps of backwashing, brining and rinsing when respective predetermined fluid flow volumes stored in a memory means pass through the resin. The regeneration sequence may be initiated when a further predetermined fluid flow volume also stored in the memory means passes through the resin. A fluid hardness sensor measures the concentration of objectionable ions for selecting the most advantageous fluid flow volume between regeneration sequences. A brine conductivity sensor determines when the concentration of the regeneration agent falls below the concentration required for adequate regeneration of the resin. An outlet conductivity sensor enables discard or reprocessing of outlet fluid below a predetermined quality. A warning/service alert signals problems or failures in the ion exchange apparatus.