Astute Observations Iron Raven!
I do have a sweetwater filter that I routinely use on backpacking trips, but this is New Mexico and Colorado I'm talking about. If it weren't for animal bourne giardia and crypto this mountain stream water would be a thousand times cleaner than most tap water in major cities. I need something that doesn't take up much room and I want to be prepared for that brown swamp sludge water source if necessary, so chem purification is what I'm after. I am aware of the dangers of Iodine, I mean they don't put a skull and crossbones on the bottle just for fun. Actually, I use a concentrated form of Iodine combined with an ion beam in my work to etch the surface of Silicon semiconductor samples for SEM analysis. The vapor that forms in the process requires a full sash fume hood and significant PPE. Actually, regarding the sublimated Iodine I'm going on information I heard on another survival forum. The survival material I was issued in SE Asia in the 1970's included Iodine tablets, but it seemed that they went bad pretty easily, especially in humid environments. If you folks think that Polar Pure is the right stuff, I'll accept that advice. As for filters, I think they are useful for casual water use, but I'd hate to be hand pumping ten or twenty gallons at a time. I'm thinking extremes here. If my wife and I had to bug out of the city and stay lost in the back country for months at a time. I want to be prepared for this eventuality as well as a few nights lost in the bush. Your advice regarding accidental ingestion of Iodine crystals is wise information. Hiding out in the back country could be complicated as hell if you suddenly needed a trip to a non operational emergency room for gastric surgery.
Kix