Add some muriatic acid first to drop your pH down a little bit. If it were my pool, I would add a quart slowly in front of a return jet, wait a few hours to let it mix. Then, retest pH and add more acid if needed. An hour or so later after you add the last dose of acid, start adding chlorine. The reason I say adjust pH first is because once your raise your chlorine to shock level (which you need to do since you have algae), you won't be able to test pH. High chlorine levels make pH readings inaccurate.

Do you have a CYA reading? What is the ingredient in your shock and in your tabs? Look closely at the tabs to make sure they don't have copper in them.

The test kit we recommend is the Taylor K-2006 or 2006C which you can get through the test kit link in my signature.