In the 70's and 80's I purified my water by drinking copious amounts of C3H7OH. I never filtered and if the water looked really bad it was boiled. I never got sick, well.... some awful pounding headaches and queasy stomachs...
Seriously, that is a horror story, OM. I'm really sorry that happened. Thank you for relaying that very vital information. My wife, who takes thyroid medication and seems prone to reactions would not fare well with iodine treatment in water. I'm going to research how it might effect her in general food intake. We rarely eat salmon, but we're having it twice next week (smoked, in pouches) as part of our dinners in the Grand Canyon. Tough enough for us to get from river to rim without exacerbating her thyroid condition. Worth researching. I hate chlorine with a passion, so I'm very happy for packable efficient filters, that have kept us safe for quite a few years, now. Off to do some reading on iodine and thyroid conditions- thanks again OM.

Edit: I didn't find anything definitive, but it appears that eating foods that contain iodine isn't going to do much for or to my wife; at least in the short term. It was certainly worth checking, though.