Two-part chlorine dioxide (Aquamira) is much smaller and lighter than water filters and works better than other chemical systems.
However, as sold it has two major usability flaws:
Behold!!! the Aquamira Enhancement Kit, which solves these problems:
This is the kit I carry. Contents, clockwise from upper left:
(Obviously, you only need one each of A and B, but I was running low.)
What you do is measure Aquamira into the graduated cylinder (using the chart for reference), let it sit the five minutes, and then use the medicine dropper to dole it out appropriately into water bottles. (Do not put the dropper directly into the Aquamira bottles, as that will contaminate them.)
Here’s the chart. You need 0.35mL (or 7 drops) of each part per liter of water.
Water mL Drops one both one both 1L 0.35 0.7 7 14 2L 0.7 1.4 14 28 2.5L 0.88 1.75 18 35 3L 1.05 2.1 21 42 5L 1.75 3.5 35 70 10L 3.5 7.0 70 140
If this info is helpful to you, or you build a similar kit, please let me know! E-mail me at firstname.lastname@example.org.
Disclaimer: While I have used Aquamira, and I have carried this kit in the field, I have not actually tried the kit in the field yet. I have plans to do so and will update this page to reflect my experiences.