I got frustrated testing twice a day and trying to get the numbers "just so"... I gave up for a few (3) days. Just tested my pool and the numbers are right where they need to be (I believe).
I have never been able to get zero CCs. The pool is old and I don't think I will, but chlorine is stable and ph and Alk are good to go. Last check with pool store, CYA was 40. All is good -- which is good, 'cause we are having our first pool party this weekend!!