A method and system for the extracorporeal treatment of blood to remove fluid from the fluid overloaded patient is disclosed that non-invasively measures osmotic pressure across a filter membrane of a blood filter. The present invention also relates generally to the H. The formulation includes between about 10% to 30% of one or more surfactants and a preferred combination of surfactants includes at least one ethoxylated fatty alcohol, one alkyl polyoxyethylene glycol, one alkanolamide and one polymeric quaternary ammonium salt. The first supply suction system and the second supply suction system have respectively chemical liquid supply sources, rinse liquid supply sources, inert gas supply sources, and ejectors.