Ever since the 3ifo long-term storage containers have been utilizing CP2's dewar boil-off for purge gas we have been getting alarms due to poor PID control following a Praxair LN2 delivery.  Today I valved-out the 3ifo line (0830 - 1600 hrs local) for the Praxair LN2 delivery and the control of CP2's level was significantly improved.