The PB put a water fill line on our hose bib. Usually I turn it on when nobody is home then go out and turn it off. Well, today I turned it on and while I was in the house, my son turned it off and we heard a loud bang in the house from the plumbing. I heard the tail end of a caller recently on a pool radio show that talked about this happening to him and I cant remember what they said caused this or how to fix it. Anybody know how to correct this? Cant be good for the plumbing.