Your hot tub IS a time machine... It will age your jewelry.
A customer once came in with every piece of her gold jewelry damaged at the solder joints. Her chains were broken, the shanks of her rings were missing where they were sized, and a diamond had fallen out of its mounting. The culprit was bromine. Bromine and chlorine both eat away at gold jewelry.
A while back a gold findings and casting company called Hoover and Strong did a controlled experiment to find out why diamond prongs were breaking. They placed platinum, 14K palladium white gold and 14K nickel white gold in various concentrations of chlorine and bromine and measured the length of time it took until the prongs failed.
Here are their results:
Results Of Each Solution
1) 5% chlorine bleach heated to 110°F, prong failure would occur after 21 hours of exposure. Only the platinum and palladium white gold settings held their stones in the worst test solution.
2) 5% chlorine bleach room temperature - prong failure would occur after 120 hours of exposure.
3) 5 ppm (parts per million) chlorine using hot tub chemicals - prong failure would occur after 312 hours or 156 days.*
4) 5 ppm (parts per million) bromine using hot tub chemicals - prong failure would occur after 384 hours or 192 days. *
5) Household detergent - no visible effects on the setting.
*based on 2 hours a day, 7 days a week
Their recommendations were to use platinum or palladium white gold heads or at the very least rhodium plate them. It is a good idea to remove jewelry when using hot tubs and pools and never use bleach to clean your jewelry.
More information can be found at Hoover and Strong Study