The number of chemical reactions that are possible to cause corrosion are beyond the scope of an internet questions. I do, however, know what is causing the metal to rust. Your "pool chemicals" are likely some acids and bases for pH up or down, a total alkalinity adjuster, and some shock chemicals containing chlorine. Chloride ions in solution are particularly good at being electron sink (a place for electrons to go). In contrast, metal alloys contain various metal atoms with different oxidation potentials that are a great electron source. The presence of chloride, and probably chlorine gas from the bottles, in the same area as metals is the reason for the corrosion. pH up or down chemicals will also cause rust, but most likely the problem is the chlorine. Clean off the metal surfaces and paint them with metal paint or find an alternate place for pool chemical storage.