A fluid circuit (401, 470A) for preparation of a medicament for renal replacement therapy, and a box (484; 494), the fluid circuit comprising: a concentrate container (430, 462; 492; 752) containing acid concentrate connected for flow communication, through a first pumping tube segment, to a medicament supply line (435; 475) that has been capped and sterile-sealed at an outlet end thereof; a bicarbonate cartridge containing dry bicarbonate buffer compound, the bicarbonate cartridge being of a type that admits water in an cartridge inlet thereby forming a saturated bicarbonate solution which is received at a cartridge outlet, the cartridge outlet being connected for flow communication, through a second pumping tube segment, to the medicament supply line; and a water inlet line connected for flow communication, through a third pumping tube segment, to the medicament supply line and connected for flow communication to the bicarbonate cartridge inlet; the first, second, and third pumping tube segments (446, 444, 442, 465) being supported by a circuit cartridge (450; 770; 800; 850A; 850B) which orients, aligns, and exposes for access the first, second, and third pumping tube segments (446, 444, 442, 465) with respective actuators of a predefined medicament preparation device; the circuit cartridge (450; 770; 800; 850A; 850B) containing a first concentration sensor station positioned in said medicament supply line downstream of a first junction where a first of said first and second pumping tube segments connects to the medicament supply line; the circuit cartridge (450; 770; 800; 850A; 850B) containing a second concentration sensor station positioned in said medicament supply line downstream of both said first junction and a second junction where a second of said first and second pumping tube segments connects to the medicament supply line, wherein the fluid circuit is packaged with the box (484; 494) such that the circuit cartridge can be detached or removed from the box (484; 494) while leaving the concentrate container and bicarbonate cartridge intact therein with lengths of connecting lines between the circuit cartridge and the box (484; 494), thereby permitting the circuit cartridge (450; 770; 800; 850A; 850B) to be installed in a position remote from a position where the box (484; 494) is installed. a concentrate container (430, 462; 492; 752) containing acid concentrate connected for flow communication, through a first pumping tube segment, to a medicament supply line (435; 475) that has been capped and sterile-sealed at an outlet end thereof; a bicarbonate cartridge containing dry bicarbonate buffer compound, the bicarbonate cartridge being of a type that admits water in an cartridge inlet thereby forming a saturated bicarbonate solution which is received at a cartridge outlet, the cartridge outlet being connected for flow communication, through a second pumping tube segment, to the medicament supply line; and a water inlet line connected for flow communication, through a third pumping tube segment, to the medicament supply line and connected for flow communication to the bicarbonate cartridge inlet; the first, second, and third pumping tube segments (446, 444, 442, 465) being supported by a circuit cartridge (450; 770; 800; 850A; 850B) which orients, aligns, and exposes for access the first, second, and third pumping tube segments (446, 444, 442, 465) with respective actuators of a predefined medicament preparation device; the circuit cartridge (450; 770; 800; 850A; 850B) containing a first concentration sensor station positioned in said medicament supply line downstream of a first junction where a first of said first and second pumping tube segments connects to the medicament supply line; the circuit cartridge (450; 770; 800; 850A; 850B) containing a second concentration sensor station positioned in said medicament supply line downstream of both said first junction and a second junction where a second of said first and second pumping tube segments connects to the medicament supply line, wherein the fluid circuit is packaged with the box (484; 494) such that the circuit cartridge can be detached or removed from the box (484; 494) while leaving the concentrate container and bicarbonate cartridge intact therein with lengths of connecting lines between the circuit cartridge and the box (484; 494), thereby permitting the circuit cartridge (450; 770; 800; 850A; 850B) to be installed in a position remote from a position where the box (484; 494) is installed.