If the 6 lbs of chlorine you added was dichlor, then that's probably why your pH dropped. However, 7.2 is actually ideal, so I wouldn't mess with it.

Keep in mind that when you have algae in the pool, the chlorine kills it, but the filter is what actually removes it from the water. That's more than likely the source of your cloudiness. I would avoid all the flocs and other additives that the pool store would have you add, and just keep your filter going 24/7, watching your pressure and backwashing as needed, and it will clear up the pool, provided that all the algae is dead.

That being said, you really need to shock the pool (Cl up to 12-15 ppm if that CYA number is correct, which I'm doubting) and hold it there until you can measure less than 1 ppm chlorine loss between sundown and sunup the next day. As the chlorine is used, add more as often as possible to maintain that 12-15, which is what it will take to kill the algae. Brush the pool daily, keep the filter running as I described above, and it will be clear in no time.

Janet