The devices and systems are medical fluid treatment therapies. The device and systems are configured and capable of operating based on small volumes of fluids. The devices and systems include a pump configured for small volume of a fluid. The pump may include a first conduit configured for inflow of the fluid; a second conduit configured for outflow of the fluid; a fluid chamber configured to move the fluid through the pump; a diaphragm configured to force the fluid through the fluid chamber by indirectly exerting force on the fluid chamber; and a connector configured to removably attach the pump to a motor.