That's interesting. I've never felt the need for the charcoal filter, but I'd like to have a prefilter. Up until now I've only used the PUR (Katahdin) hiker, which has both carbon and two prefilters, but is heavy at 12oz. I have the mini now but haven't used it in the field, and after hearing stories of how easily it clogs, I'm thinking a prefilter is a good idea. I'm wondering if the silicone sealer will adhere well enough to PET plastic, as it normally requires special adhesives.

Let us know how this works.
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Always remember that you are absolutely unique, just like everybody else. -Margaret Mead