If you haven't done so already, check out Aqua Mira for chemical water purification. Use the forum Search feature to search all of the forum threads for more info on Aqua Mira. Also, check out the product "Catalog" on this website for more info.
You might decide to switch from Iodine to Aqua Mira. And then again, maybe not, but at least, if you haven't done so already, you will learn something about another, possibly superior, means of chemical water purification.
Hope this info helps.