CYA is cyanuric acid which is also called stabilizer. It would probably be a good idea for you to post a complete set of current water testing results taken with a drops based kit. Cary is right - if you go to the pool store to have your water tested, don't let them talk you into buying a bunch of stuff. And she is also right that one dose of shocking won't cure it. Keep at it for another couple of days and run your pump 24/7 for now.