If you're a backpacker you need a reliable yet lightweight
method for purifying and filtering water in the wild. Most
commercial methods are either bulky and heavy or need supplies
such as salt and/or batteries. Instead you can make a gravity
water filtration system using two water bladders, a $17 Aquamira
Frontier Pro filter or likewise, and a pack of chlorine dioxide
purification tablets. YouTube user and veteran backpacker Jason
Klass demonstrates the light weight, versatility, and low cost
(around $40 for everything) of this setup. Basically you fill
your "dirty" water bottle directly from a river, lake, or
stream, add a purification tablet, and connect your clean water
bottle to the Aquamira filter. The other side of the filter is
connected to the water resevoir you drink from. Hang the dirty
water from a tree branch and keep the clean water on the ground
and in half an hour you'll have a couple of liters of clean
water to drink. Why does this system use both a chemical and a
mechanical filter? The aquam