Photographs by Julien Gontard
The MSR Guardian Gravity Purifier is the upgrade on the original Guardian Purifier Pump, it uses the same advanced technology to remove bacteria, protozoa, and viruses from water, yet offers them in a high volume, pump free design, offering purified water on demand.
The Guardian Gravity Purifier uses a 0.02-micron hollow fibre filter, as well as a carbon component to pull out chemicals, tastes, and odours. Originally developed for the U.S Military to enable their soldiers to drink water practically anywhere in the world, the Guardian Gravity Purifier is the only purifier that meets the NSF Protocol P248 military testing standard, meaning that as well as being used for the public joe, like you or me, it can also be used for the military.
So how does it work? Well, it’s all to do with the Hollow Fibre technology MSR have developed. Within the purifier, there is a bundle of spaghetti-like straws dotted with microscopic holes which are big enough to let water molecules through, but too small for bacteria, protozoa, and viruses. It is also the only purifier that offers such protection, with such a fast flow rate – 1 litre every 2 minutes. While this is slower than most pump-actioned filters, the Guardian Gravity Purifier is much lighter, more packable, and capable of storing and carrying water.
Who needs this? This purifier is perfect for anyone looking to spend an extended period of time outdoors and wants to be able to carry a light load. It’s a water treatment system that does it all anywhere you go. It has a 10-litre collection bag, meaning that whether you’re solo trekking in the wild or going on a large group hike you can fill the bag up anywhere from a tap to a stream, making it as convenient as you need it to be.
Finally, there’s a very simple yet effective way of controlling the flow, using a little clip on the hose that you pinch in to limit the rate or halt it altogether. A cap seals the end of the hose, and this has a clever little adapter that lets you fasten a number of different types of bottles onto it securely. Cleaning it out is easy as well, all you need to do is open up the ‘purge hose’ which will flush out debris and keep the flow rate nice and high.
When you’re not using it, it packs up into a little ripstop pouch no bigger than a Nalgene water bottle. MSR say after a minimum of 3000 litres is when you should look to replace the cartridge, which has an indicator on, so you know when that time is near.