What is the ingredient in the chlorine granules? If it is cal-hypo, you can use it for awhile until your calcium hardness approaches 400 but after that, you'll need to switch to bleach.

You must be using test strips to get a range of 30-50 for CYA. If you have a reputable pool store nearby, ask them to test your CYA for you but don't let them talk you into buying a bunch of stuff. When we find out if your CYA is closer to 30 or closer to 50 we'll decide if you need to bump your CYA up any. If so, then if the granules are dichlor, you could use it for a short time. If you are closer to 50, then as Jan said, you would be better off just switching to bleach now.

Post CYA when you get a more accurate reading and work to get that pH up ASAP!