I'm going back and forth these days between relying upon my Steripen (the Adventurer Opti model) and AquaMira. Pardon me while I share my thoughts, in writing, with you all. (I write for a living, so I do this all the time.)
I know that using a chemical treatment saves pack weight, so that's one of its merits. When I've gone out onto the trails with AquaMira, I've taken two full 20 oz bottles of water from home with me to the trailhead. I drink all the water in one bottle before I stop to refill it, then after refilling it and treating the new water, I set the treated water aside while I drink out of the second bottle of water from home. This two-bottle approach gives my newly treated water anywhere from 60-120 minutes to work before I even take one sip.
Yet the last time I went out, I came down with giardiasis. Not fun, as I'm sure you're aware. My hypothesis is that 1) I failed to "bleed" the bottles well enough to eliminate all the remaining untreated water from the bottles' mouths. The competing hypotheses, of course, are that 2) I needed to wait longer after first treating the new water, or 3) I needed a more effective pre-filtration method to eliminate cysts/protozoa from the new water, or 4) a combination of any/all of the three competing hypotheses. Regardless, it's made me start wondering about my ability to use AquaMira.
In the past, I've used my Steripen in combination with its FitsAll prefilter and an old 1 L Nalgene bottle. Weighty, I know. But for some reason (maybe technophilia, or chemophobia) I found the use of UV water treatment my best option. However, the Steripen can't be used with narrow-mouthed bottles. (I've yet to experiment with using the Steripen in a bottle whose mouth is the size of a Gatorade bottle.) This approach seemed to work effectively, although it required me to insert the prefilter into the bottle's mouth, and then submerge the bottle into a water source, in order to fill it. I operated the Steripen according to the manufacturer's rules, but on my first use of it (in my ignorance) I neglected to bleed the bottle… and (guess what) came down with giardiasis.
Now here's my current thoughts:
The first (and most obvious) thing is that regardless of what water treatment I use, if I keep working the way I have in the past, I must never forget to bleed the bottle.
The second is that I need to work on my prefiltration methods. (So here I go…)
If I cannot submerge a bottle into which I've inserted the FitsAll, then I'll need to find another means of prefiltration, perhaps by using one bottle to gather water directly from the source, then pouring that untreated water carefully though the FitAll into another bottle, and then treating it. If no untreated water got onto the mouth of that second bottle, I'd not have to bleed it. If I could treat the water in the second bottle with the Steripen, I'd not have to wait to drink it. But in order to treat that water with the Steripen, the bottle would need to have a wide mouth; that, of course, would likely mean a significant weight penalty.
Treating the water with AquaMira would eliminate that penalty, since the mouth size of the bottle containing the water undergoing treatment would be inconsequential. I could still keep my two-bottle arrangement. But rather than have a bottle of water undergoing treatment as I hiked, I'd need to carry a bottle of untreated water, which would be filtered/treated later (presumably, when the bottle of treated water was empty and/or when I arrive at a water source). That would require me to wait a good amount of time between treating water and drinking.
I could elect to augment the AquaMira/two-bottles-of-home-water approach with a third water vessel (perhaps a cut-down Platypus 1 L) that I could use to collect water from sources. When I'd need to refill one of my bottle, I could collect water in the third vessel, pour that water through the prefilter into the empty bottle, and treat it as I hiked, drinking now from the second bottle. With no contact between the bottles' mouths and untreated water, I may be able to forgo bleeding. And if I chose the third vessel wisely, the weight penalty could be minimal.
My third idea is that I might be able to replace the Steripen completely, even though its and effective, technically precise, and lightweight option. It seems that if I could work with AquaMira in combination with 1) an effective means of prefiltration and 2) keeping the bottles' mouths clean, then the Steripen wouldn't be needed. That would mean that the risk of dead batteries would be eliminated.
Pardon me, again, for sharing all this text with you, but I think on paper. Reading back over my text, I seem to feel that my best option (given where I hike most often) is to augment the AquaMira/two-bottles approach. But like all writers, I feel like I can't completely trust my own reading, especially when reading my own text.
So…
What do you all think? Am I thinking along the right path? Or can't you tell, from what I've written? Do you have any ideas for me?

