A comprehensive set of ternary interaction Pitzer parameters for solutions of the system Na-K-Cl-SO4-PO4-HPO4-H2PO4 was calculated from water activity and solubility data acquired from an extensive literature review and water activity data obtained from isopiestic experiments. This work is a continuation of part I, wherein results concerning binary phosphate systems are presented. (C) 2014 Elsevier Ltd. All rights reserved.