I'm seeking to disinfect a Platypus gravity water filter made with hollow fibers. My main concern is to address any mold / mildew that may have developed inside the hollow fiber filter due to long term storage.

The manufacturer suggests

"To disinfect your Platypus filtration system, fill it with a solution of unscented household bleach and water, using a concentration of 2-5 drops per liter of water. Close and swirl for 10 seconds. Leave filled overnight.

"Filter solution through any filters and/or hoses, then rinse system (including filters and hoses) three times with hot water. Let air dry.

"Note: for an eco-friendlier option, use a chlorine-free, hydrogen peroxide-based bleach alternative.

I called the customer hotline and asked if I could just pour in hydrogren peroxide from the pharmacy, but they said I should just stick to the recommended guidelines. The agent also reminded me that if I use chlorine bleach, it's best to use a fresh bottle. Do you think the same is true for hydrogen peroxide bleach?

Could I dilute 2-5 drops of the pharmacy 3% hydrogen peroxide with one L of water?

I looked at the Seventh Generation non-chlorine bleach MSDS, and it lists hydrogen peroxide at 3-5% concentration:


Any insights would be welcome. Thank you!

  • 2
    $\begingroup$ The manufacturer gives specific instructions, confirmed by customer service. What advantage could you gain by making up your own procedure? Bleach and H2O2 are both good, but not equivalent. The H2O2-based bleach is a powder. But I am not rigid - I might tolerate 6-7 drops of chlorine bleach from a year-old bottle. Chlorine is a great bactericide and cleaner-up. And it is not eco-unfriendly, just aggressive. $\endgroup$ – James Gaidis Jul 11 at 14:13

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