In an embodiment, a dialysis fluid cassette is disclosed. The cassette includes a plurality of walls defining at least one valve chamber, a dialysis fluid inlet, a dialysis fluid outlet and a dialysis fluid pathway. The cassette further includes a baffle extending from a first one of the walls to an opposing second one of the walls. The baffle includes an end fixed to a third one of the plurality of walls and a free end. The fixed end separates the dialysis fluid inlet from the dialysis fluid outlet and the baffle and the plurality of walls are constructed and arranged such that the flow of dialysis fluid along the pathway defined in part by the baffle slows as the flow approaches the free end of the baffle.