Your PF is 4.8. Walmart 8% bleach, per gallon, is equivalent to 0.7 lbs of chlorine gas. So 1 gallon will add 4.8 x 0.7 ppm chlorine to your pool, or 3.4 ppm.

Likewise, if you use dichlor (61% available chlorine in some forms), 1 pound would add 4.8 x 0.61 = 2.9 ppm.

I'm not sure why your pH is moving; there are multiple possibilities. Focus on managing your chlorine, keeping your pH between 7.0 and 7.8, cleaning your SWCG. Run things for a week or two so you establish 'normal' patterns.