When I’m off hunting and fishing at the camp, I usually bring clean water. But I like to have backup option. The thing is that « real » and safe filters are way too expensive to use merely as backups. That’s why I like to use chlorine dioxide (by Pristine), that give a better taste than Iodine. Also, the steripen (the Classic model) offers quick, easy and very safe way to treat water. But I was a little disapointed with its prefilter, that is 40 microns wide.
Here’s a quick way to transform an emergency straw type filter into a gravity flow drip system that can filter nasties down to 3 microns. Exit the tubing, valve, collapsible water container, glue, CamelBak, and ... technology.
Keep it simple and light!