Brominating products are the preferred sanitizer for most spas. Since spas are usually covered or indoor, the bromine is not exposed to UV rays so the lack of a stabilizer is not a problem. Moreover, bromination has some distinct advantages:
Whether using chlorine or bromine, all spas should be oxidized periodically, based on bather loads. There are a lot of compounds that need to be oxidized, especially the oil, sweat and dirt that wash off a bather’s skin. With bromination, oxidation also has a second major benefit as it reactivates the bromides, changing them from used-up bromide ions into the powerful bacteria-fighting hypobromous acid.