I'm a newbie with a spa due at my home in two weeks. I've never had a spa before, but we've maintained a 24,500 gallon pool with no problems. We will be closing the pool about the time the spa arrives. My main question is what do we do differently to maintain spa water. It seems we can use the same chemicals, ph up, ph down, chlorine, chlorine shock, non-chlorine shock, a water quality product like pool frog, etc although in much smaller quantities. With spas, I continually see bromine listed as a main chemical. Is this the equivalent of a non-chlorine shock? If so, is it a secondary sanitizer, meaning the water still requires a chlorine shock once a week or so to keep it sanitary? Thanks in advance for any comments on what experienced spa owners now use for sanitation.