I am looking For a water purifier. I am new to backpacking. I have been looking at the Grayl Geopress, but as I shop in places that specialize in hiking equip and talk to some people who I know to have extensive experience in hiking, have never heard of Grayl. Is that because it is more of an international product and not just a back packing item? What is my best option as a water purifier for light back packing?I would like to do some longer hikes, so I want to invest in decent equipment but it can be confusing.