Not having success with BBB in my hot tub

[chem geek]

I heard somewhere that you were suppose to use unstabilized chlorine in a hot tub, not sure why or what that means.

The reason you heard that it is best to use unstabliized chlorine in a hot tub is because CYA (which is introduced with stabilized chlorine) reduces chlorine effectiveness. The bacteria that causes hot tub itch (Pseudomonas aeruginosa) is somewhat resistent to chlorine (and likes hot temperatures which is why it is found in hot tubs and not in pools). So not using CYA or at least keeping the CYA at lower levels allows for greater disinfection and prevention of hot tub itch.

Of course, if you don't use CYA, then you will lose chlorine very quickly if the hot tub is exposed to sunlight and you will even lose the chlorine more quickly in darkness due to greater outgassing (especially if you add extra salt to your hot tub, which you shouldn't). If you keep your hot tub covered most of the time, then you reduce the loss from outgassing.

So there is a tradeoff for how much CYA to use and I am not clear on exactly where the best level should be, but suspect it is on the lower side -- not more than 30 ppm.

Richard