WHOA.... Hold on a minute! Alex, that's elemental iodine. Do you have any information that it is safe and equivalent to the iodine compounds/products meant for human consumption in water purification applications?

Hmm. I don't think there is any difference, except that tablets have some stabilizing filling making bare hands handling easier, and crystals in the Polar Pure are less pure. The elemental Iodine is what's so efficiently killing pathogens. Let me know if I'm wrong.

UPD: Google Polar Pure Ingredients. All it contains is 99.5% pure Iodine crystals.

I asked Potable Aqua a couple of years back what the shelf life of their iodine tablets was. It was one year from when the bottle was opened or four years from the date of manufacture. Which ever came first.