HOT TUBS: Calcium (and Bromine)

[chem geek]

This is a new thread taken from this linked thread since I've gone off topic.

As for Spa / Hot Tubs
yes, you bet calcium is added...

The BBB method works just fine for hot tubs, just substitude bromine for Bleach...lol

Oh & BTW, I find maintaining hot tubs is actually easier than pools... ( I dunno why)...lol

Looks like you wrote this the same time I wrote my "correction" response. Anyway, thanks for filling me in a bit on spas (and for the compliment). I wonder why the calcium is pushed so much for hot tubs. Is it:

1) hot tubs have some plaster/grout parts, possibly in the cover or rim or somewhere???
2) water balance of calcium carbonate really does inhibit corrosion of metal parts in hot tubs and not having any calcium can cause serious damage
3) calcium isn't really needed and the pool store guys just want to make lots more money

Though I made this sound facetious, I really do want to know if calcium is honestly needed for hot tubs and why.

With regard to bromine, is your hot tub indoors? If it's outdoors than I don't understand why bromine is used instead of chlorine. If it's for reducing the smell of chlorine, that would only come from chloramines so with proper dosing I don't see why that would become a problem. Is it normal to use bromine in hot tubs even if they are outdoors? Even if it's indoors, why not use chlorine? If the buildup of chloramines is a problem, then the regular use of a maintenance dose of potassium monopersulfate (MPS) non-chlorine shock should prevent that and I bet is still cheaper than using bromine over chlorine.

Richard