A method for quantifying the fluidization characteristics of ion exchange resin is proposed. This method entails the application of an integral version of the Serial model by means of an optimisation technique. In this study, it is applied to the laboratory-measured expansion curves of five different type of resins of varying skeletal structures, at various system temperatures and in columns of varying diameter. The model is shown to account satisfactorily for alterations in system temperature and horizontal dimensions. It is suggested that this algorithm is suitable for the optimisation of receptacle dimensions, used for accommodating ion exchange resin in a fluidized state. It would appear that the Serial model theory satisfactorily represents the expansion of a poly-sized fluidized bed of resin.