CYA stands for cyanuric acid which is also sometimes called stabilizer. It is kind of like sunscreen for your chlorine. All outdoor pools need some or otherwise you quickly lose the chlorine to the sun ---- which is what will happen in your pool for the first few days. After you start using the dichlor which is a stabilized form of chlorine which means that it has chlorine and CYA in it, your CYA level will gradually rise and you'll start to see your chlorine lasting longer. You don't want too much CYA; most pools do well at around 50ppm. So, once you hit that, you'll want to switch back to only using bleach.

For now, while using bleach and having no CYA, each time you add bleach, aim to get it up to about 5-6ppm. It won't stay there long and as I noted in a previous post, you'll probably need to add it a couple times per day so you make sure it doesn't drop to 0. Once you get CYA in there, the needed chlorine level will change. Read this for more info about the relationship between CYA and chlorine:> http://pool9.net/cl-cya/
(After the CYA level builds up, you'll be able to go to testing and adding chlorine in the evening only.)

When you start using dichlor, wait about 10 days to 2 weeks before you test the CYA for the first time or else you'll just be wasting your testing reagents. The test can't read anything level below 30ppm. It is not a test that you do too often.