[http://www.mec.ca/AST/ContentPrimary/Learn/HikingAndCamping/FoodAndWater/ChoosingAWaterTreatmentSystem.jsp][1] Mountain Equipment Coop has a pretty good info section on water purification with backpackers in mind. The basic science is outlined and complemented with the pro and cons of available systems. MEC is a great place for outdoor supplies in Canada, by the way. [1]: http://www.mec.ca/AST/ContentPrimary/Learn/HikingAndCamping/FoodAndWater/ChoosingAWaterTreatmentSystem.jsp

[http://www.mec.ca/AST/ContentPrimary/Learn/HikingAndCamping/FoodAndWater/ChoosingAWaterTreatmentSystem.jsp][1] [1]: http://www.mec.ca/AST/ContentPrimary/Learn/HikingAndCamping/FoodAndWater/ChoosingAWaterTreatmentSystem.jsp