During last year's quest to water purification, I mostly looked at microfiltering options, neglecting chemical and UV methods. I've not looked properly into UV yet because of the need for batteries, but I have dug further into chemical water treatment. There is actually a whole range of products on the market, based on no less than 5 different chemicals: It is rather difficult to judge which one is best. And as you can see, the type of chemical seems highly dependent on variable country regulations. Since LifeSystems sell both Chlorine and Chlorine dioxyde on the same market, you would expect them to clarify this. Well, it's not very conclusive:

Chlorine is the most widely used disinfectant.
Chlorine Dioxide is the most effective disinfectant.

Right...

Whilst checking the product differences between countries, I've also noticed a bit of confusion around the Katadyn MyBottle capabilities. There is a significant difference between the fact sheets on the American and on the European websites. The European one features a single bottle called "MyBottle", eliminating protozoa, bacteria and viruses with "ViruPur". This is the one I bought. The American one however, features two bottles: "MyBottle Purifier" and "MyBottle Microfilter" (*). The former eliminates viruses with "ViruStat", but the latter does not. Problem: the latter looks really similar to the European one, which is supposed to filter viruses! All this starts to look rather dodgy to me...

Reading the product manuals is rather off-putting. For example, the MSR Purifier Solution manual starts well with:

Harmful if swallowed.

And carries on with a lot of warnings like this:

This pesticide is toxic to fish and aquatic organisms.

But my favourite is:

If swallowed:
* Call Poison Control Center or doctor immediately for treatment advice.

This is supposed to purify filthy water into "drinkable" water. How the hell are you supposed to use it if you cannot swallow it?

There is also a variety of chemicals to remove the taste of chlorine/iodine, but it starts to make the whole process a bit fiddly on the run: pump 1 minute to get your liter of water, add chlorine, wait 5 minutes, add neutraliser, wait 3 minutes, and finally drink.

I guess Chlorine Dioxide might be the best choice, as it appears to have less after-taste than the others, thus avoiding the neutralisation stage. Silver ions are tasteless, but apparently more for conservation than actual treatment.

Ultra chemical water...

(*) Whose names are by the way somehow consistent with the MSR terminology, with their "SweetWater Microfilter" and "SweetWater Purifier". Only the latter eliminates viruses.