I don't think I'd buy a secondhand filter, either. The filter element has a limited life and if it's used, there's no way to know if it's past its useful life.

Consider the chorine dioxide tablets or a DIY gravity filter (I made my own, similar to the one ULA used to make, using a Katadyn Hiker Pro filter element, plastic tubing and fittings, and a Sea-to-Summit UltraSil 8-liter dry bag).

EDIT, LATER: Post in Make Your Own Gear section on how to do it.


Edited by OregonMouse (01/12/12 10:20 PM)
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May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey