I decided to test CYA tonight after the pool being open for 3 weeks. I tested it after a week and I would swear the reading was up around 70, but tonight's reading was 30. I retested just to make sure. I put what I had left into a stocking and hung it in the skimmer basket. I came back about an hour later, the stocking was empty. Either it had a run in it or it developed one. I assume the CYA is now in the filter and is dissolving? How soon until I can backwash again? I vacuumed just before I did this so I should be good for at least a week.