In the most recent issue of Backwoods Home magazine (which I highly recommend, BTW) a reader’s letter caught my eye. Headlined “Bleach ineffective as disinfectant above 100 [degrees],” the letter from Tim Sheehan of Rosharon, Texas points out that “[T]he disinfecting properties of bleach are nil at temperatures above 100 degrees.”
Anybody know if this is true? And is he talking Fahrenheit or Celsius? I’m relying on bleach as the primary ingredient for our post-SHTF water-purification needs, but frankly about a third of our days here in Northern California can be over 100 degrees Fahrenheit.
Heating water up to 100C for 10-15 minutes is a pretty good way of purifying it. I suspect he means 100F.
Ted
Try some iodine instead – I used it on camping trips with good success to purify water. Simply put a few teasspoons solid iodine in a small bottle with ethanol (Everclear or vodka works fine) and add about 1 teaspoon of the liquid per gallon of water. Refill the liquid as needed, as long as there remains solid iodine in the bottom of the bottle.
Tastes like what I imagine as the flavor of piq sweat, but giardia and pathogens can’t live with iodine in the same water jug.
Polar Pure Iodine Crystals are easy to use and work!! If you want anything with Iodine crystals you better get it quick. They make d-r-u-g-s with them and are hard to find now. You can buy what is left in stock but when it is gone it is gone.
Fred
The latest iodine tabs that they’re selling require two tabs per quart- one of iodine, and a second to neutralize the iodine taste. I used them backpacking last year and they really improved the taste. REI sells them, so does wally world I think (camping section).
I’m not sure why 100 degrees would reduce the effectiveness of bleach.
According to the MSDS for sodium hypochlorite here –
http://physchem.ox.ac.uk/MSDS/SO/sodium_hypochlorite.html – it decomposes at around 40C which would be a little over 100F. Bleach is 5% sodium hypochlorite I believe…
Well, there ya go. Thanks to all and especially Kevin.
My concern, as will be seen when I post about our water storage, is that I have been filling up our water containers with water and the requisite few drops of liquid bleach, then rotating every six months or so.
The problem is that the water is stored in our garage, which — although partially insulated — can easily hit 100 degrees on the right day. So should I rotate my water more often? I haven’t seen any icky green goop in the stored water yet, but not all bacterial growth is visible….
I have a doctor in the family so I’m not too concerned about the new iodine restrictions. (Although I’ve certainly been watching the posts about PolarPure on Survivalblog with some dismay.)
I’ll try a smell/taste test next time I rotate the water. If the bleach ain’t working, I’ll move to iodine.
Call the bleach company, David. They ought to have something on this.