Generally I finding that using
Chlorine Dioxide purification tablets, covers my needs in the sort of environments hiked / camped in, if water ever needs to be purified. Unless someone is in a hurry, or encountering very grim water that would require some pre treatment filtration, the tabs work well with minimal after taste and I believe they
probably match the 0.02 cover of filtration systems (viruses, etc)
Light and compact in a backpack, there is also nothing mechanical to fail. Wrapping foil has expiry dates on them, but if this is something to be adhered to or not, I currently don't know (
but I admit to disposing of some found in the house once after noticing some were now two years after the stamped expiry date, rather than gamble). Prior to those, for years my means of purification was Iodine tincture when in places like Latin America or South Asia, and it served me well when caught out somewhere and feeling very thirsty. Horrid after treatement taste, but tolerable when you are extremely thirsty somewhere.
I believe that the E.U banned the sale of Iodine tincture in recent years?
Bulky and popular pump filters were available at the time, but looked like such a hassle to me , especially when you read so many reports of total mechanical failure just when somebody was relying on them. Currently, along with the Chlorine Dioxide tablets, the other purification means in my pack is the
Sawyer SP128 Mini filter.
In terms of effectiveness, the Sawyer SP128 Mini is 0.01 microns, so not as comprehensive as their other larger (
and more expensive) model, the
SP129 Sawyer Squeeze Filter which filters at 0.02 microns (viruses, etc), but I didn't foresee myself requiring that cover for recent outings. According to their website, the SP129 is currently in use by UK Special Forces. True or not, I don't know, but it is not the first filter company making such claims, so I suspect this may be individual purchases rather than wholesale supplied?
Prior to getting the Sawyer Mini, the other non tablet purification method in my backpack during UK outings was the
DrinkSafe Systems TravelTap, something that I eventually lost patience and confidence with. It screwed onto the top of an accompanying water bottle, and your 'squeeze' action on the sides of the bottle created the filtration once turned upside down. However, sometimes water dripped or dribbled out of the sides of the top seal, when applying the pressure, leaving you unsure if this was treated water, or had just contaminated your destination vessel or your mouth.
DrinkSafe systems would respond to several reports of this, by claiming this was due to people over tightening the thread, over applying pressure or not fixing the cap on correctly. To be fair, it seemed that sometimes this was true, but I eventually lost patience with a product that was dealing with something so important but could so easily cross contaminate. To be fair to them, they now appear to use a slightly different bottle. If this solved the problem for good I don't know, but I moved on.
For me, the value and main use of the SP128 Mini filter being carried with me is as a 'on the fly' device that saves me cutting into existing clean water supplies in my pack. For example, earlier this year, if finding and camping near a spring in Israel, the bulk of the next day's drinking water could be purified with tabs but just before leaving the area in the morning I could guzzle directly from the spring using the supplied tube on the SP128 Mini Filter, hydrating me without cutting into the day's supply.