I've had my beads since around July 2011 and they have been working great, but it seems like I am needing to rehydrate them more frequently. If I don't rehydrate once a week...max every other week, my level starts dropping below 65%. Is this normal? I bought the XL Tube (2000 cubic inches) and I have a humidor that is 14 3/4" x 9 5/8" x 7 1/8". I bought a tube larger than needed because I tend to open my humidor somewhat frequently, and wanted a quicker recovery time as they advertised.

Is this normal, and is there anything I can do do get them back to the way they were when I bought them?
Thanks in advance for your input!