When an IEX resin has been used for some time, impurities may build up in the column causing loss of resolution or increase in back pressure (shown on the pressure monitor or seen by gap formation on the top of the column)...
Always do regular cleaning-in-place (CIP) of the resin according to the manufacture’s instructions to prolong the lifetime and resolution of the resin. But first check if the problem is actually caused by the column before starting a cleaning procedure. Disconnect one piece of equipment at a time and re-check the pressure each time. A dirty on-line filter is a common cause of increased back pressure. Check the same stage during each run, since the back pressure can vary within a run.
