For the dry acid, it's probably best to either add it through the skimmer with the pump running--or if it were my pool, I would probably dissolve it in water first, then pour it slowly in front of the return to let it help dispurse the acid. That's how I add my bleach, too....and it doesn't matter which order you add them in, and you don't need to wait any length of time between additions. Once the chems are in the water, they're fine.

Janet