Balanced flow dialysis machine

A method of equalizing fluid flow in a dialysis cassette for a renal failure therapy machine, the method comprising:

• providing the dialysis cassette comprising:
• a housing for the dialysis cassette configured and arranged to be placed in the renal failure therapy machine,
• a flexible membrane attached to the housing, the flexible membrane and the housing cooperating with the renal failure therapy machine to operate a plurality of valves,
• fluid pathways within the housing for routing renal failure therapy fluids, and
• a balancing apparatus operable with the plurality of valves, the balancing apparatus including at least one inlet port and at least one outlet port;
• configuring the at least one inlet port and the at least one outlet port to allow removal of air from each port;
• providing a separator configured to move within the balancing apparatus, wherein the separator is provided within a moving cylinder or piston that is controlled by a motor or a shaft of the renal failure therapy machine, and wherein the balancing apparatus includes obstructers configured to prevent the separator from moving to opposing ends of the balancing apparatus;
• detecting a pressure of a fresh renal failure therapy fluid;
• detecting a pressure of a used renal failure therapy fluid;
• and
• controlling the plurality of valves so that a pressure of the fresh renal failure therapy fluid to the balancing apparatus is approximately equal to a pressure of the used renal failure therapy fluid to the balancing apparatus by (i) selecting an operating pressure based on the detected pressure of the fresh renal failure therapy fluid and the detected pressure of the used renal failure therapy fluid, and (ii) adjusting one of (a) the pressure of the fresh renal failure therapy fluid or (b) the pressure of the used renal failure therapy fluid to be equal to the selected operating pressure.