The number 1 reason people have trouble with the
SLAM Process is they take shortcuts and don't follow it step by step. Your best chance for success is to SLOW down and be diligent about every step it says.
That's why I want you to get to a good CYA level and pH before you begin adding chlorine. You also need to brush you pool as often as possible to break up the biofilm on the algae so the chlorine can get to it.
Once you get your pH to 7.2-7.4 and have the CYA sock in the water then begin adding the chlorine.