The cartridge can include a mixing component for mixing different solutions so as to form a product solution. A mixture of different solutions can be transported into the mixing component where they combine to form a product solution. The mixing component includes a plurality of variable volume reservoirs in liquid communication with one another. The product solution can be repeatedly transported from one of the variable volume reservoirs to another of the variable volume reservoirs until the desired degree of mixing is achieved. Once the desired degree of mixing is achieved, the product solution can be transported directly to a product chamber within the cartridge or can be treated further before being transported to the product chamber.