I do, but I've never had the Purigen turn pinkish. It just turns browns over time, and after re-charging, the bag retains some light beige coloration around the edges, that's all.
I only feed the Tetra color granules once or twice a week, though - are you feeding the granules often on a weekly basis ?
( but you know, I may have a little color identification problem - what appears beige to my eye might seem more pinkish to you - LOL, but it's possible.)
When you re-charge, particularly if you use full strength bleach rather than 1:1 with water, the Purigen particles should return to their original off-whitish color.
At any rate, it shouldn't be any problem, IMO - the Purigen should retain it's effectiveness, at least for several re-charges.