With your FC at that level, don't try to adjust your pH as long as it's reading the way it is. There are two reasons:
1) Measuring pH at FC levels of 15 with a CYA of 40 is highly inaccurate.
2) Chlorine is generally more effective at lower pH than at higher pH.

IOW, keep on doing what you are doing, run your pump 24/7, test and adjust FC 2 to 3 times a day, vacuum to waste everyday. Brush the walls and bottom every day to knock algae loose.

Carl