lower ph = chlorine is more effective
keep ph between 7.2 and 7.6
keep it on the lower side to cambat algae

Free Chlorine is at it's most effective state when kept between 2 & 4 ppm (depending on water temp) with a PH neutral (low to mid 7's) and a stabilizer (cyanuric acid) level of 30 ppm (mostly shady) to 50ppm (mostly sunny) level. It is not as effective of a sanitizer when the PH is in the 8's or when the stabilizer levels are high.
If your pool is cloudy I'd recommend a few gallons of cheap unscented bleach over the bagged shock you used and a 24 hour straight pump run. Look at the water clarity tomorrow and repeat if necessary or go back to your standard run time.
You should keep your PH and Alkalinity constant year round at 7.2-7.4 and Alkalinity at 90-110. Let your Free Chlorine go down to 1.5 with water temp below 65, 2-3 with water temp 65-85, and 3-4 with water temp over 85.
There are other variables that are important to plaster and equipment longevity but these 3 are the most important for water clarity, sanitary disinfection, and swimmer comfortability. Avoid Combined Chlorines by shocking to breakpoint chlorination when you detect them.
It may roll off my keyboard easily and seem hard to achieve but it really isn't. By getting ahead of your water it's much easier to keep up with.

See ya,
Kelly