7 responses

  1. stberhard
    October 20, 2008

    Actually chlorine dioxide is extremely effective a low temperatures, nearly as effective in the low 30's as it is at ambient temperatures.

  2. Earlylite
    October 20, 2008

    Do you mind if I ask how you know that?

    Here's an excerpt from an Environmental Protection Agency Report showing that Chlorine dioxide's effectiveness in killing cryptosporidium (cysts) decreases in cold water.

    "In a more recent study, LeChevallier et al. (1997) found that reducing the temperature from 20°C to 10°C reduced the disinfection effectiveness of chlorine dioxide on Cryptosporidium by 40 percent,

    which is similar to previous results for Giardia and viruses. Gregory et al. (1998) found that even under the most favorable conditions (i.e., at a pH of 8.5), required doses to achieve 2-log

    Cryptosporidium inactivation do not appear to be a feasible alternative, requiring doses of more than 3.0 mg/L with a 60 minute detention time. At neutral pH levels, the required doses may be more than 20 mg/L."

  3. lori
    October 21, 2008

    I was just over in a backpacking forum where there was a thread of comments about the batteries in the Steripen needing to be warm to work and difficulties in freezing weather.

  4. Earlylite
    October 21, 2008

    that's good feedback. I was on the verge of buying a steripen. Were there any suggestions about viable alternatives beside boiling? Would carrying your batteries in your pocket keep them warm or would using lithium batteries which are cold resistant help?

  5. lori
    October 22, 2008

    There are threads in several forums where I've read about the pen being unreliable, breaking, or having issues in the cold. Here is the most

    recent one I've run across.

  6. lori
    October 22, 2008

    I meant to add – I have not tried the pen myself because of the reviews I've read and I don't like relying on something that takes batteries. I'm one of those who carries a filter and Micropur tablets for backup. Carrying the filter in the inside pocket of my jacket or between layers of shirts wouldn't be fun, but it would have to do. Fortunately I have ULA gravity filter and the size isn't unmanageable.

  7. Earlylite
    October 22, 2008

    I have the same attitude to anything the requires a battery in the backcountry: best to be avoided. My primary purification strategy is a first need filter/purifier and I also bring Micropur tables for backup in my murphy bag. I am hestitant to bring the first need on winter trips since it is big, so I might just switch to a disposible Aquamira Frontier Pro<a />;, which can, as you say, be worn close to the body to keep it from freezing.

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