I was talking to guy on the jobsite the other day. He tells me he has an ozonator in his hot tub, and that he only adds about 1 teaspoon of chlorine every week. No other chemicals added, at all. So, is there "stuff" growing in his spa that he doesn't know about? Will this procedure be OK for a spa? After reading these forums for the last month, I don't want to get in his hot tub. For that matter, I don't want to get in any hot tub until I know what's in it.