I live in Canada and just got a 6 person SoftTub this year. The guide recommends the use of Bromine since it holds up to the hot temps better than chlorine, which is why I find it strange that SoftTub US doesnt want you using Bromine. My upkeep is super easy, just bring up the bromine reserves when you first fill it (5-6 ppm) and then use the bromine floater and adjust your PH every so often. I also have a "shock" which has a PH lock and a bunch of other stuff I put in once every week. I also squirt in a little clarifyer which is suppose to help with the filtering etc etc. not sure if it actually works. I too was told to dump the water every 2-3 months which I am about to do at the end of this month so I can do it again in Dec to try and bridge over till spring (I dont want to change 300 gals of water in the dead of a canadian winter)

But so far so good, I usually keep the cover on unless we are using it, so there is no worry about the sun breaking down the bromine levels quickly.

I heard somewhere that you were suppose to use unstabilized chlorine in a hot tub, not sure why or what that means.