I used to disinfect water when I was hiking long distance one summer using Iodine tablets. I would always mix a quarter packet of powdered lemonade with the quart of water and Iodine tablet to kill the Iodine taste (at the same time!). I am assuming that the iodine worked despite the citric acid in the packets as I never got giardia and know the water along the AT in the South is pretty contaminated...
What exactly gets neutralized? According to my experience, not the germ-killing properties...
And I don't understand why iosupplementers are supposed to take C if it serves to diminish the iodine...