The present invention relates to a dialysis machine having an extracorporeal blood system； a dialysis fluid system having a dialyzer； having a control unit, wherein the dialysis machine furthermore comprises a balancing chamber having two balancing chamber halves for a balanced infeed and draining of dialysis fluid to and from the dialyzer, wherein a line is provided through which the dialysis fluid is conducted to the balancing chamber, and wherein a mixing chamber is provided in which the fresh dialysis fluid or a component thereof is located and which is directly or indirectly connected to a de-airing line closable by a valve； wherein the dialysis machine has a control unit that is configured such that the control unit opens and closes the valve once, or a number of times, in the operating state of the special air separation of the dialysis machine when the balancing chamber half of the balancing chamber in fluid communication with the named line is in its high-pressure phase.
