BBB in hot tub too?

[waterbear]

main difference is that you will be dosing with teaspooons to ounces instead of cups to gallons or pounds! Also, you might find dry acid is easier to dose than muriatic. It's not easy to measure out a teaspoon of muriatic acid!

[Tomcat]

Chlorine doesn't last as long at the elevated temps (or so I remember reading somewhere). Bromine is better. I bought a jug of bromine tabs ($15) and they lasted me nine months, so not a big expense there. I have a floater and put one or two new tabs in once a week. I tried using muriatic acid, but would always overshoot my target ph, so now I use dry acid (also very cheap). When needed, I do use borax as ph up. I also shock once a week with a non-chlorine shock (also very cheap - I think like $3 a bottle that lasted seven months). I've found the hot tub maintenance to be very cheap and easy. Your milage may vary due to frequency of use and any "beverage" spillage or addition of other organic compounds :-)

[waterbear]

Chlorine works fine in a hot tub. It is a bit more temperature and pH sensitive than bromine but is easy and the least expensive.
There is a lot of misinformation about bromine. Bromine tablets in a floater are NOT enough. First, sodium bromide has to be added to the water to create a bromine bank that the oxidizer (chlorine, MPS, or ozone) converts into hypobromous acid. Bromine tablets do contain either chlorine or MPS but they dissolve very slowly and it can take a long time to get enough bromine reserve in the water for them to work properly if you don't add the sodium bromide first. IMHO, the best shock for a bromine spa is bleach.

I have used both in a portable spa. They both have their own unique sets of problems. For example, I found that pH control was much harder with bromine. pH was always dropping.