I have had good luck with this guy from Katadyn. I have mainly used it to pull water from lakes. We have to carry so much water when we go out in to the desert and at about 8 pounds a gallon, the weight adds up. I wish there were more oppotunities for me to purify water out here, but hey it's the desert.

http://www.katadyn.com/usen/katadyn-prod...adyn-vario-usa/