A machine-readable medium embodying instructions that may be performed by one or more processors, the instructions comprising instructions for pumping blood from a patient's blood stream into an access line, instructions for introducing an anticoagulant solution into the pumped blood, instructions for filtering the pumped blood, instructions for delivering the pumped blood from the filtering step to a return line, instructions for introducing at least one substitution fluid into the pumped blood, instructions for introducing a calcium solution into the blood traveling through the return line, and instructions for returning the blood back to the patient's blood stream.