I can’t remember the last time I wrote about a piece of gear, so here goes:
Lightweight backpackers have a point when they complain about these heavy, ungainly filters. Using a bandana and chemical purification is the far lighter alternative, particularly if you’re getting far enough into the country where the water-safety issues are less of a worry.
But what if you’re just out for a long, sweaty day hike and don’t feel like carrying a gallon of water the whole way? This is where my Katadyn Hiker filter has come in handy a bunch of times. I just toss it in the bottom of my daypack and it’s always there, like dehydration insurance.
Using it is admittedly ungainly: you have to plop down near a water source, usually getting your butt muddy, and get the hoses out and make sure the right one goes in the water and the other goes into the filter outlet, all the while ensuring the inlet hose doesn’t contaminate the outlet hose. Then you have to pump all the water, which flows faster than you might suspect. Ten minutes and you’re back in business, waterwise.
I try to remember to air-dry the filter element after I’ve used it. Otherwise the moisture in there starts getting skunky after awhile.
The other main consideration — especially if yours has been sitting in the bottom of a backpack for weeks or months — is to pump run some water through the filter system for several pumps to get a clean flow going; otherwise you’re pumping milky-looking water into your Nalgene that you probably don’t want to be drinking. Try to pump it onto the ground to avoid polluting your water source.
Almost forgot to mention the main advantage of a filter: the water just tastes better than it does with chemical treatment. There are issues with filters not catching every known pathogen (viruses, for instance) but if you’re hiking in known terrain it shouldn’t be much of an issue.
Newer and niftier filters are coming on the market all the time, but this one’s a trusty standby.