Don't know what kind of pool you have--if it's vinyl lined, then alk is a little high at 170, but it really doesn't have much effect on the pool--I'd leave it alone 'til you get your algae issue taken care of. You don't mention a CYA level in your pool, and the level you need to take your chlorine to inorder to kill the algae depends on your CYA level. Either way, 8.5 isn't high enough to do you any good.

While you're shocking, you can go ahead and vaccuum, but you also need to be brushing daily and have your filter running 24/7 to help rid the pool of the algae once it dies.

Janet