What's in the granular shock?
Borax is a good way to raise pH and I would most certainly raise the pH of this pool. Do you have a K-2006? You can get a good idea how much Borax you'll need using the Base demand test. It'll take more Borax than Soda Ash. Start with half the calculated amount, let it dissolve / mix for a few hours then test again. You do, however want to get the pH into the readable range of the test as soon as you can.