The specification discloses a portable dialysis machine having a detachable controller unit and base unit. The controller unit includes a door having an interior face, a housing with a panel, where the housing and panel define a recessed region configured to receive the interior face of the door, and a manifold receiver fixedly attached to the panel. The base unit has a planar surface for receiving a container of fluid, a scale integrated with the planar surface, a heater in thermal communication with the planar surface, and a sodium sensor in electromagnetic communication with the planar surface. Embodiments of the disclosed portable dialysis system have improved structural and functional features, including improved modularity, ease of use, and safety features.