Treatment fluid devices methods and systems

Embodiments include a consumable medical device comprises a rigid cartridge to which a film is adhered to form a fluid channel and a damper chamber. A portion of the film forming the damper chamber has a wave-like shape adapted to roll onto a tip of a damper. The damper has a plunger to minimize peristaltic pressure in the channel. The cartridge may include conductivity measurement channels. Crosstalk may be minimized by using different frequencies or time division for reading the channels. A stable dialysate concentrate containing sodium lactate may be used or generated with the system. The concentrate may be formed to higher concentration than feasible with a single component concentrate by forming two containers of concentrate, each containing a fraction of a total quantity of sodium lactate required for a predefined number of dialysis.