System and method to efficiently clean a blood filter

A renal therapy system comprising:

• a blood filter including a plurality of hollow fiber membranes;
• arterial and venous lines in fluid communication with the blood filter;
• a blood pump for pumping blood through the arterial and venous lines and the blood filter;
• a treatment fluid pump in fluid communication with (a) a treatment fluid side of the blood filter or (b) the arterial or venous line;
• and
• a control unit controlling the blood pump and the treatment fluid pump during treatment and at least one of the blood pump and the treatment pump during a filter cleaning sequence in which (i) a physiologically safe fluid is transferred back and forth across the insides and/or outsides of the plurality of hollow fiber membranes, (ii) the physiologically safe fluid mixed with air is transferred across the insides and/or outsides of the plurality of hollow fiber membranes at least one time, and (iii) the physiologically safe fluid mixed with air and blood residuals loosened or removed from the hollow fiber membranes is transformed to drain.