Don't worry, I am just using them for new plaster start up, but am starting to wonder if they have gone bad. I have had 3 pucks in since a week ago today and added 2 more 2 days later and I am still getting the .5-1 reading when I test. I am adding liquid chlorine in as well ( started 3 days ago) but without much if any CYA in the pool right now, it evaporates pretty quickly. Seems I am putting 1 96 oz bottle in every day since to maintain around FC 3.
The bucket of pucks stayed closed in their container in our shed over the winter..it did get pretty nasty for here weather wise, but the shed door was closed and there was no direct contact with precip.