I just recently drained and refilled our pool due to a CYA level in the 150-200 range. After doing this, I have been checking chemicals daily. Yesterday my FC was at 0, as it is today! I am using the TFP calculator and it told me to add 110 oz bleach, which I do, but then by the next morning there's NO detectible chlorine. Same thing happened this am. Instead of adding bleach, I threw in there trichlor tabs bc I KNOW that'll work. (As a side note, by CYA is now 0, so adding a few pucks will only help me). Could the 0 CYA have anything to do with the missing FC after adding a whole jug of bleach? Am I doing something wrong? Missing something?? Yesterday's numbers FC .5, CC .5, pH 7.7, TA 110, CYA 0.