another thing to think about for all you condom carriers out there...

Do you know what a quart or half a quart of water in a condom looks like? How will you get accurate dosages of iodine/MP1? Which brings me to my next point - have you actually tried to fill a condom with water? And you can carry a full condom in a bandanna sling of sorts.

Dosage of purification methods, ease of carry, and ease to fill are the reasons I went with gerber bags instead of condoms.