Hello! I have purchased a Katadyn Vario microfilter for water filtration on the trail. Now that I am focusing on going ultra light, I think it may have to go. It works great. I can pump two liters in one minute. Not sure why that should matter though. Its not like I am ever in a really big hurry on the trail to get water. So...for me...that's wasn't the selling point. I just liked it and bought it. I may use it with other scenarios. Like with the family or something. But for an ultra light pack...its too much...so would some of u veterens give me some idea of what u do? U would rather not filter pond or creek water through grass coal and dirt through a dirty sock. Im not looking for survival mode filtration. ;-) thanks in advance.