My Beads Have Turned Yellow

I have been having trouble with my humidor keeping humidity. My cigars have seemed dry lately. I replaced the battery on my hygrometer and salt tested it. It was accurate. I'm not perilously dry, 61%, but I would prefer a little moister. I looked at my beads today and a good deal of them are yellowed. I've had them a little over a year.

I'm thinking this is ammonia that has evaporated. Any thoughts? Should I just bug Scooter for more beads?