Methods for the central preparation and distribution of a concentrate to a plurality of medical treatment devices are disclosed comprising supplying a stream of substantially only water to a central container which includes a single salt composition at least partially in solid form, producing a substantially saturated solution of the salt composition in the central container, and distributing the salt solution to a distribution conduit which includes a plurality of concentrate connectors whereby the salt solution can be distributed to the plurality of medical treatment devices. Methods for disinfecting this apparatus, the apparatus itself, and containers for use in the apparatus are also disclosed.