A renal therapy system is described. The system comprises: a dialyzer； a balancing system configured to equalize flow volume of renal failure therapy fluid to the dialyzer and from the dialyzer； and a controller configured to control the flow of fresh renal therapy fluid and the flow of spent renal therapy fluid for the balancing system so that a pressure of the fresh renal failure therapy fluid to the balancing system is equal to a pressure of the spent renal failure therapy fluid to the balancing system.
