A hemodialysis system includes (i) a dialyzer; (ii) a blood pump; (iii) a blood cassette operatively connected to the dialyzer and the blood pump; (iv) a dialysate heater; (v) first and second peristaltic dialysate pumps; and (vi) a dialysate cassette separate from the blood cassette, the dialysate cassette including an organizer configured to support a drain tube, a to-dialyzer tube and a from-dialyzer tube, the cassette further including a first pumping tube, a second pumping tube and an inline fluid heating pathway, the cassette when mounted for operation orienting (a) the first pumping tube for operation with the first peristaltic dialysate pump, (b) the second pumping tube for operation with the second peristaltic dialysate pump and (c) the fluid heating pathway for operation with the dialysate heater.