A hemodialysis machine comprising: a dialysate flow path for delivering a flow of dialysate solution through a dialyser, the flow path including: a flow balancer for achieving a balance in the dialysate solution flow volume observed between an inlet and an outlet of the dialyser over the course of a treatment, the flow balancer comprising a first flow balance pump having an inlet valve and an outlet valve and a second flow balance pump having an inlet valve and an outlet valve, wherein each of the valves (28, 26, 32, 36) has a pneumatically operable membrane covering an inlet port and an outlet port, the valves (28, 26, 32, 36) being substantially geometrically identical to one another, and wherein the pumps (12, 14) are switchable between two modes of operation, a first mode of operation in which the first flow balance pump is arranged in the dialysate line upstream of said dialyser and the second flow balance pump is arranged in the dialysate line downstream of said dialyser, and a second mode of operation in which the second flow balance pump is arranged in the dialysate line upstream of said dialyser and the first flow balance pump is arranged in the dialysate line downstream of said dialyser, characterised in that the first flow balance pump inlet valve, the first flow balance pump and the first flow balance pump outlet valve are mirrored about a centreline A-A to respectively the second flow balance pump outlet valve, the second flow balance pump and the second flow balance inlet valve, so as to provide a dialysate flow path that is fluidically substantially identical irrespective of which pump chamber (12, 14) is pumping into or out of the dialyser. a flow balancer for achieving a balance in the dialysate solution flow volume observed between an inlet and an outlet of the dialyser over the course of a treatment, the flow balancer comprising a first flow balance pump having an inlet valve and an outlet valve and a second flow balance pump having an inlet valve and an outlet valve, wherein each of the valves (28, 26, 32, 36) has a pneumatically operable membrane covering an inlet port and an outlet port, the valves (28, 26, 32, 36) being substantially geometrically identical to one another, and wherein the pumps (12, 14) are switchable between two modes of operation, a first mode of operation in which the first flow balance pump is arranged in the dialysate line upstream of said dialyser and the second flow balance pump is arranged in the dialysate line downstream of said dialyser, and a second mode of operation in which the second flow balance pump is arranged in the dialysate line upstream of said dialyser and the first flow balance pump is arranged in the dialysate line downstream of said dialyser, characterised in that the first flow balance pump inlet valve, the first flow balance pump and the first flow balance pump outlet valve are mirrored about a centreline A-A to respectively the second flow balance pump outlet valve, the second flow balance pump and the second flow balance inlet valve, so as to provide a dialysate flow path that is fluidically substantially identical irrespective of which pump chamber (12, 14) is pumping into or out of the dialyser.