Most of the camping products are not pure I2 crystals anymore. More common is TGHP, or tetraglycinehydroperiodide. The package I saw claims that this compound is more stable in water, providing a residual antimicrobial effect.
Chemical water purifier tablets in general are hard to find at outdoor stores in the last few years. Most backpackers nowadays use filtration systems to purify drinking water, rather than chems.
------------------
Ellis D. Tripp
-- Neither the author of this post, nor this website or its owners advocate the use, manufacture or sale of any controlled substance. All posts are for information and entertainment purposes only, and should not be considered meaningful. War is Peace. Ignorance is Strength. Big Brother Loves You. Have a Nice Day! 