PRESUMEDLOST completed testing of various water containers and iodine tablets. He asked me to post it for anyone who may be interested.<br>============================================<br>Results of the Great Water Container Test:<br><br>The object was to determine whether any of the water bags under<br>consideration for "mini" kits were affected adversely by iodine-based<br>water purification tablets.<br><br>Test was conducted on the following:<br><br>Glad (brand) zipper storage, "Double Lock" seal, 1 qt size, 7" x 8"<br><br>Ziploc (brand) freezer bag, 1 qt size, 7" x 8"<br><br>Trojan (brand) latex condom, non-lubricated (now rolled into a circle<br>instead of a narrow oval, and not nearly as small a package as I<br>remembered)<br><br>Reynolds (brand) oven bag, small (formerly regular) size, 10" x 16"<br>(turns out that I drastically underestimated the capacity of these-<br>even leaving plenty of room to twist the top, the "small" size hold 3<br>liters easily).<br><br>Blue Bird (brand) round toy rubber balloon from the National Latex<br>Company, Ashland, Ohio<br><br>Kordon (brand) "Breathing Bag", for shipping of live fish (courtesy<br>Mr. William Vannerson, supplied in 3 different sizes).<br><br>Procedure:<br><br>Testing was done using Potable Aqua (brand) water purification<br>tablets, tap water ("city water", chlorinated, fluoridated and who<br>knows what else), an empty 1 liter Evian bottle for measurement, and a<br>fiberglass wash tub.<br><br>Initial expectations were that it was probable that there would be no<br>failures in the test period. Nevertheless, it clearly had the<br>potential to become a comparison test, so it was thought appropriate<br>to make some attempt at a uniformity of iodine concentration. The<br>smallest apparent container was the balloon, but it seemed likely to<br>hold a liter, so it was decided to use one liter in each of the<br>containers. To encourage confidence in the results from a limited<br>test period, 4 Potable Aqua tablets were used in each container, twice<br>the recommended concentration (though I think I remember that they<br>used to recommend 4 tablets per quart for "cloudy" water, I couldn't<br>find that on the current label- maybe that was the military version).<br><br>After examination, the largest size of the Kordon "Breathing Bag" was<br>chosen for testing. All the sizes supplied seemed to be made from the<br>same thickness of material, the smallest size looked to be too small<br>to hold a liter, and the middle size supplied looked too useful to<br>waste...<br><br>Filling the various bags with a measured liter from the bottle was not<br>a problem. The condom and the balloon, however, presented some<br>problems.<br><br>The condom distended and filled much more easily from just the weight<br>of the water than I had supposed. Having tried it from the tap, I<br>anticipated no problem filling it from a bottle (for measurement), and<br>there was none- once the neck of the condom was stretched to admit<br>outside air as well as the neck of the bottle. I admit I wasted 4<br>tablets and one condom doing this, but I have to admit that I think it<br>would be easier to fill from a trickle in the wild than I had<br>envisioned.<br><br>The balloon was much more of a problem. It could be filled from the<br>tap, but stubbornly resisted being filled from the bottle no matter<br>what I tried. In the end, since the balloon was assuming a shape<br>identical to the already-filled condom, it was filled from the tap and<br>the size was just matched by eye. I anticipate that it would be<br>difficult to fill one of these without a tap in field conditions.<br><br>All of the containers not having a built-in zipper-type seal were<br>simply twisted and tied.<br>Testing began November 2, 2001. It was deliberatly decided that no<br>attempt would be made to agitate the water to aid in the dissolution<br>of the iodine tablets, other than an occasional palpitation to<br>ascertain the continued strength of the bags- so that if there were<br>sensitivity of the material to the tablets, the test would approximate<br>a worst-case scenario, the tablets effectively just sitting on the<br>bottom until dissolved by time.<br><br>November 15, 2001 (two weeks).<br>There have been no failures, and no discernable weakening of any of<br>the containers. The two "zipper" style bags, "Ziploc" and "Glad"<br>brands, have both lost appreciable amounts of water, either through<br>insensible leaking or evaporation, but both retain more than half the<br>original water, and they seem sound enough- no visible leaks, no<br>brittleness or weakness. None of the other containers have apparently<br>lost any water at all, so the best current guess is that the "zippers"<br>don't seal as effectively as one might hope, at least over a period of<br>weeks. All the containers were examined, none leak visibly, and there<br>is no apparent weakening of the material even in those places where<br>brown stains remain from the iodine tablets.<br><br>It was originally intended to run the test for a month, and perhaps it<br>will go on, but no further change is really expected. for one thing,<br>the water in each of the containers has unexpectedly lost it's initial<br>reddish brown tint and returned to being colorless.<br><br>Tentative conclusion: At twice the "normal" concentration of iodine,<br>over two weeks, none of the containers exhibits any deterioration or<br>leakage. Whatever the reason for the Teflon-lined caps on the iodine<br>tablet containers, it would seem that any of these proposed water<br>containers should be at least resistant enough for it not to be a<br>realistic issue.<br><br>A secondary test was done comparing the rupture strength of a Reynolds<br>Oven Bag to a Kordon "fish" bag. In informal testing, comparison<br>proved to be very difficult.. the Kordon bag deformed (permanently)<br>with comparatively little force, but proved to be very elastic indeed<br>before rupturing. The Oven bag resisted deformation more, but on the<br>other hand the material punctured before stretching nearly as far. In<br>the end, it could only be said that they are probably roughly<br>comparable in overall strength, though very different in<br>characteristics.