A method for treating dialysate solutions used in dialysis wherein dialysate is treated in an early part of a dialysis treatment session by external infusion of bicarbonate solution into the dialysate circuit to eliminate the need for bicarbonate requirements in concentrates used for preparation of precursor dialysate (priming) solutions and/or for a solid bicarbonate layer in a sorbent cartridge. Dialysate is treated in a latter part of a dialysis treatment session by introduction of sterile dilution water to reduce sodium concentration in the dialysate. The method provides a more efficient and reduced use of dialysate fluids, electrolytes, sorbent cartridge materials, equipment scale, or any combinations of these, while maintaining purity standards and applicable physiological ranges for bicarbonate, sodium, and other dialysate solution components over the course of a dialysis treatment session.
