>>356310You're getting the wrong idea. You arent running it though more contaminants. The gravel and sand act as sieves to catch the larger stuff that would otherwise clog the charcoal, which is the real point to the device. Charcoal is an excellent way of purifying water, it absorbs toxins, flavors, and smells that would make the water unpalatable. Brita filers are basically packets of charcoal dust, for example.
Sometimes you'll be in a situaltion where you have a crystal clear mountain stream to drink from. In that case boiling alone is fine. Other times your only source within miles will be a dank puddle with a half rotted animal carcass and actual shit floating in it. You'll probably wanna filter it first then.
