HTH, sodium hypochlorite is the base of most bleaches and releases 80% of its weight in chlorine. I think Janola is 4.2% HTH so is about 3.4% chlorine.
You also need to allow for the chlorine demand because it is free available chlorine at 2ppm that you want. In other words, the more organics in the water, the more you will need to add. The only way to get it right realy is to get a chlorine testing kit (from swimming pool suppliers)