History. I have has this hot tub for about 4 years. I tried the chlorine method at first and epic fail cause my kuds would go in while I travel and wouldn't add chlorine.
So I have been pretty successfully with Bromine Tabs.
I use about 3 tabs a week -10 days. I use the sticks to test and appears to have go Evelyn of bromine. Purple on the stick to pink. All other parameters seem ok.
It's 450 gallon Jacuzzi Brand Spa with an ozonator. It have a built in tube that I just add the tabs that fits in one of the filters to distribute.
It seems lately that only when our kick on the jets and turbulence is created it gives off a noxious gas that makes everyone cough.
Even after we leave the jets off and the cover for a while then jets back on it happens again. I have let up on the chemicals for a week or do. Then the bromine level droos and still have the coughing fumes.