Hi Rickmart, and welcome to the forum!

Keep in mind that "shock" is actually a verb, something you do to the pool, rather than a noun, something you put into the pool. To shock a pool simply means to raise your chlorine to an elevated level based on your CYA readings. You can use cal-hypo like you have been, dichlor powder, or liquid chlorine (bleach).

I don't think it's the cal-hypo that's making your pH fluctuate, because it's usually fairly pH-neutral. Often if the pH flucutates too much, you need to change your TA values, but without actual numbers to look at we can only guess at the problem. Can you post a set of test results (taken with a drop-based kit, no strips!!) for us to look at? How are you testing your water? Define "all over the place"?What form of chlorination do you use on a daily basis?

We'll be glad to help, we just need a little more information