Great, thanks for clearing up the backwashing process. I was never told to turn off my pump while switching up the process. Thanks so much for the information! Apparently, my gauge is broken because it goes to 30 psi when turned off. I will have to go purchase one of the tester you have mentioned because I have been using strips. I do have city water though. How do I figure out how many gallons my pool is? As far as the shock, it has cal-hypo in it. My normal chlorine source is the tabs. Thanks again for your time, and I will get back to you regarding the water testing.