The way we did our pool (18 x 36 inground) - there really was no scientific method. We dumped in about 6 or 8 laundry scoop size cups of Cal Hypo (Calcium Hypochlorite, commonly known as "shock"). Then we put several pounds of stabilizer in an old pair of nylons and tied it to the ladder (it dissolves very slowly over a couple days). Then we filled up the skimmer with Chorine pucks (tri-chlor).

The pool immediately turned a sort of yucky yellowish color. We hit it with several more scoops of Cal Hypo the next day. By the end of the day, it was already turning sort of a light green to clear green color.

By the 3rd day, it was almost 100% clear. So I can't really say that we did any exact measuring at all - it was basically hit it hard with lots of chlorine for 2 days.