As long as you still have green in the water, you haven't killed all the algae yet. With a CYA of 90, you need to shock the pool by taking your chlorine up to 20 ppm and hold it there by testing and adding more chlorine as often as possible. You need to maintain that 20 ppm level of chlorine until the pool clears all the way up, and until you can go from sundown one night to sunup the next morning without losing more than 1 ppm of chlorine. At that point you can let the chlorine drift back down, but with the CYA that high, you can't ever let it drift below 5 ppm. (See the "best guess chlorine chart" in my sig for the details).

I suspect the "shock" they're having you use is dichlor, which contains CYA. Your CYA is high enough already, and adding more CYA just means you have to raise your chlorine higher. So I would use plain, unscented bleach in this case.

Unfortunately, the "green to clean" contains ammonia, and ammonia can create quite a large chlorine demand in your pool, in addition to what the algae is using up. So...it may take several days to get to the point where you are holding your chlorine overnight, but it's a necessary part of clearing up the mess.