Since your chlorine has dropped so low, go ahead and shock the pool up to about 15ppm using the reference amounts I gave you in a previous post.

Most people need to add a little bleach every evening or maybe every other evenings.

Each evening, test the water for chlorine and pH. (Don't try and test pH when the chlorine is high, however, or you'll get a falsely high reading.) After you test, add enough bleach to get your chlorine back up to 6ppm. The next evening, test again. If you find that you didn't make it through the day without having your chlorine drop below 3, then take your chlorine up to 7ppm. Continue to do this each evening. You'll soon learn how high you have to take the chlorine so that you don't let it drop below the minimum from the Best Guess Chlorine Chart (in my signature below) before the next evening. Does that make sense?

You only need to test the alk every few weeks and if you don't use any calhypo, you don't even need to test CH. Only test the CYA if you add some and then, wait a week after the addition before you test it to make sure you let it dissolve.

(If you find that you have trouble keeping chlorine in your pool, you may want to bump your CYA up to around 50ppm.)