New endless pool user water treatment

[PoolDoc]

Waterbear, I'm not sure that there are any allergies to "sulfates" (=SO4).

There are definitely allergies to "sulfa" based antibiotics, and there are people who are allergic to "sulfites" (=SO3), and there are even allergic reactions to certain antibiotics, like "neomycin sulfate". But, an allergy to "neomycin sulfate" is not a "sulfate" allergy, any more than an allergy to "doxycycline hydrochloride" is a hydrochloride (HCl) allergy.

However, there are numerous medically reported cases of allergies to "persulfates" such as =SO5 or =S2O8 .

The distinction matters, since the commonly used "Dry Acid" or "pH Minus" is sodium hydrogen sulfate, but is NOT an allergen. However, the often promoted potassium monopersulfate, apparently IS a potential allergen, though possibly not at pool usage levels. The DuPont Oxone MSDS, dated in 2000 (archived at thread 14395), reports

Skin contact with the product may cause allergic skin reactions in sensitive individuals. Human patch tests with the product diluted in water at concentrations up to 150 ppm did not cause allergic skin reaction.

However DuPont's May 2011 Canadian SDS does NOT report this reaction. So, I'm not sure that MPS (generic Oxone) would be safe to use in the case of individuals who had already been sensitized to persulfate by the persulfate-based denture cleaners. But it sounds like an allergic reaction is unlikely unless you are ALREADY sensitiized.