Hello everyone. I've been using this site for quite a few years with my pool and hot tub and love all the advice given. My question is about recommended levels for Bromine, PH, Alkalinity, and Hardness for hot tubs. It seems like everywhere you read on the internet and even on the spa chemical bottles, they seem to recommend 4-6 ppm bromine, 7.2 - 7.6 PH, 80-120 ppm alkalinity, and 150-300 ppm hardness. I've also seen alkalinity recommended from 100-150 ppm and hardness from 100-200. I know I've seen some recommendations on here to be different than these numbers as well. Why is there so much varying agreeance on what the proper numbers should be? I understand I can just look on this site and use those numbers and be fine, but you would think there would be a standard agreeance that should work across the board for everyone based on your hot tub type.