You need to get that pH up. Chlorine, in bleach form, may temporarily raise your pH, but it is for a very short period of time, so don't adjust your pH down just for that. Chlorine in trichlor or dichlor form will drastically drop your pH. So....You need to add some Borax, I'd start with about 1/2 box, slowly into the skimmer with the pump running, breaking up clumps, wait a couple of hours to circulate, retest, then add more if you don't have a pH above 7.0.

Just want to caution you that taking advice from the pool store and from here will get you into trouble and be VERY confusing. You really need to either stick with advice from here, where we are driven to help you get your pool under control, or stick with the pool store's advice, where they are driven to make profits for the pool store. Trying to do both will end badly, I promise!

Janet

Edit: After re-reading the thread, I see that you already have pH up, which you can use if you want instead of the Borax. It's the same stuff, only more expensive.