have you tried chlorine ? bromine is stronger than chlorine so chlorine is a lighter option ,
basically if you want to try chlorine the best time to do this is from a empty spa after you have flushed !
quick note ! example . . . if your tub is on bromine then its classed as a bromine tub you can add chlorine into it but its still a bromine tub whatever you do
if you have a tub on chlorine and want to go down the bromine route you can add bromine to the chlorine and the tub then becomes a bromine tub bromine takes over
in a nut shell if your are on bromine and add chlorine it doesn't become a chlorine tub
if you are on chlorine and add bromine its a bromine tub ( just see bromine as the strongest )
there's nothing wrong with either option obviously with bromine you don't get the chlorine smell
quick note aswel guys if you look at your Tub water and see it sort of cloudy or misty or lets say you open your lid and you get a really strong chlorine smell hit you its ready for a rapid shock !!
how chlorine works is , chlorine gets old of all the bad bacteria etc in your tub and holds onto it it doesn't let it go it kills it and holds it , so when its cloudy etc it needs to all be burned away and how you do this is just apply a rapid shock