A hemodialysis system including (i) a dialyzer, (ii) a blood circuit including a blood pump in fluid communication with the dialyzer, (iii) a dialysate circuit including a dialysate circulation pump in fluid communication with the dialyzer, the dialysate circuit further including a sorbent cartridge for cleaning used dialysate, (iv) a dialysate reservoir, (v) a reservoir pump in fluid communication with the dialysate circuit and the dialysate reservoir, (vi) a supply of concentrate for reconstituting dialysate in the dialysate circuit, and (vii) wherein the hemodialysis system is configured to electronically weigh the dialysate reservoir and the supply of concentrate.