I ran a test using the TF100 kit and found that my CH level is in the range of 30 - 40 PPM. The Water Balance for SWGs article in Pool School recommends a CH level of 50 - 300 PPM for vinyl pools. The Owners manual for my Jandy AquaPure SWG recommends a CH level of 175 - 400 PPM. Should I target 200 PPM? How important is the CH level in a vinly pool?