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This information has been known for years. There are no great revelations in this article. It actually promotes the purchase of a hot tub. It is much safer to soak in your spa than it is in your jetted bathtub.It is too bad that home resale value, in my area anyway, increases with a "jacuzzi bath" in the master or I would tear mine out and replace it with a nice non jetted bath.A little bleach in water run through the plumbing is a good idea for jetted baths.
Actually, I have spoken to a few electricians and they said as long as I have the copper pigtails and Cu/Al wire nuts I am OK. I have them on all the recepticals in my house.Interesting enough electricians use aluminum wire to route the outside electrical to the box.
I'll read that article on hot tubs causing cancer referenced by Hot Tub Man, once I finish my cigar and brandy.
Maybe I'm wrong but I believe that the way a whirlpool tub is made that there is no water left in the pipes after you drain it.
If your talking about the moisture in the pipes then should there not be a problem with the moisture around the top of a spa? The bottom of my spa cover should be black or green by now.