A cartridge configured to be connected to a blood treatment apparatus, the cartridge comprising a cartridge inlet (127, 327), a cartridge outlet (128,328) and a plurality of chambers (121 -126) where each chamber is configured to hold a concentrate in powder form. A flow controller (105, 305) is configured to provide a flow passage from the cartridge inlet, into a single selected chamber (121, 321 ) of the plurality of chambers and from the single selected chamber to the cartridge outlet. The flow controller is movable between a plurality of positions, such that a position of the flow controller defines which of the plurality of chambers is the selected chamber. A related blood treatment apparatus is also described.
