and within the error tolerance of this pump of u2212 10 the machine thus accepts the obtained solution without giving any alarm signal however the content of potassium magnesium and calcium is about 50 higher than originally set since the contribution from the ion bag 27 consists of 100 and the contribution from the a concentrate container depending on its degree of concentration is up to at least 50 such an increase of in particular the content of potassium ions can be life threatening for the patient in order to solve this problem it is possible to use ion selective meters which measure the concentration of potassium magnesium and or calcium such meters are however expensive and complicated to use since the calcium content is raised it may be possible to indicate this error since calcium carbonate might precipitates this however takes a long time and is difficult to measure in accordance with the present invention the above problem is solved in the following way the problem occurs due to the fact that the dialysis machine has to be adapted for using both liquid concentrate for the a concentrate and a combination of powder formed and liquid formed concentrate by means of the powder cartridge 16 and the ion bag 27 thus there have to be two conduit paths which fulfill this need in accordance with the present invention the conduit 15 from the rod 13 is moved to connect to the lower pivotal arm 18 of.