Hi All! I've been lurking and reading a lot on this forum since early January when I got this spa, and really, really appreciate the wealth of knowledge here!
I'm using the 3-stage bromine process and an OTO-type test kit. It's my understanding that you can't easily distinguish between chlorine and bromine without a bromine specific kit like the Taylor 2106, and if you add the proper amount of sodium bromide (to get 30 ppm) at each tub fill-up, then there isn't any real need to test for it.
So my question is, when I add bleach, (say 1/4 cup of 8.25% bleach in 130 gal water) about how long does it take for the chlorine to dissipate so that only bromine is left, and what I see on the OTO test is actually bromine not chlorine?