phosphocellulose longevity

[JMARTINEZ at AZCC.ARIZONA.EDU]

How fragile is phosphocellulose?  I need to prepare a phosphocellulose column
as part of a fractionation protocol and would like to calibrate it with some
test mixtures before I put the real stuff on.  However, if I interpret
Whatman's product literature phosphocellulose cannot be left in aqueous buffers
for any length of time.  Is this correct?  What do you chromatography experts
do when using phosphocellulose?  Any feedback would be appreciated.