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Sterilizing Hydration Reservoirs with Efferdent

This year, I’ve had a hard time preventing red mold from growing in my Platypus hydration reservoirs. I don’t know why mold started to be a problem this year, but I think I’ve finally found a way to clean it out of my bladders and prevent it from returning.

The secret is Efferdent, normally used as an anti-bacterial cleaner for dentures, but gentle enough for sterilizing the inside of platypus water bladders. To use, fill the hydration bladder up to about 2/3 of capacity and drop 1 Efferent tablet into the bladder for each Litre of water. After a bit, the tablets will start fizzing and turn the water in the bladders blue. The fizzing oxidizes any bacteria present in the bladder, killing and dissolving it. For maximum effect, tip the bladder over and make sure the blue solution touches all surfaces in the interior of the bladder. When the blue water turns clear in that classic Efferdent way, rinse the bladder out throughly with clean water, fold it up and recap until next use.

Updated: 2014.

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  1. placing a few drops of grapefruit seed extract mixed with 1/4cup of hot water will kill any fungus or mold instantly. it's really inexpensive too. handle with care though as it can burn skin at 100% concentration.

  2. I have also found any of the baby bottle sterilizing liquids or tablets works as well, like Milton's.

    I have not tried Efferdent, if I can find it I will try it.

  3. Any drugstore in the US in the denture aisle.

  4. Rinsing then folding up with the lid will just cause more mold to grow. I have used hydrogen peroxide to clean those bottles, but only when they just had water in them, not when they were moldy. But then we don’t rinse with water afterwards. Just leave the lid off and let the peroxide evaporate out.

  5. You can use alcohol to help the bladder dry out quickly before storing.

  6. I wish I had this tip 15 years ago when I bought my first of many collapsible hydration bottles!

    Awesome tip… Thanks for sharing.

  7. David Katzenstein

    I use vinegar and let it air dry. Then a quick rinse before filling on my next hike.

  8. BrianForbesColgate

    Air it out after cleaning … you can make a hanger by cutting one upper arm from a heavy plastic hanger … put a bit of duct tape over the cut ages to protect any rough bits. Then slip the bladder opening over the horizontal bar and hang to dry. The bar will help keep the sides from touching so it dries completely.
    After it has thoroughly dried, store the bladder in the freezer between uses … it will keep anything from growing in there.

  9. I used the denture tablet and rinsed my bladder and hose several times. I used for the first time since last year and my water tastes funny.

    Did I miss a step or is it just time to replace the 10 year old bladder?

  10. I stuff a balled up paper towel in the fill hole leaving the cap off. The paper towel keeps dust/dirt/bugs(?) from getting in, but allows the bladder to dry and stay dry until next use.

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