Question:
I am looking to buy a portable water filter that has a high capacity (1,000gallons or more) and will filter down to the 2 or 3 micron level.

Answer: Katadyn Pocket and combi filters are rated to last up to 13,000 gallons,however they are fragle, and a lot of people complain about them, saythey are hard to pump. The way they are designed is the filter elementis renewed by scraping away some of it, but as the element gets loadedup, if you just pump it harder it drives the particles deeper into theelement, requiring more scraping to renew it :/ i think they just don'tknow how to use it. Used correctly it pumps easy, but slow - so when itgets real slow, clean the element instead of pumping harder. The combiscrews right on top of some common plastic bottles. The new and improvedpocket filter has a tube that extends from the outlet.

But they won't filter out viruses like hepatitus. My system combines aKatadyn with Polar Pure (iodine treatment with indefinate shelflife,treats up to 2000 quarts and costs $10).

This is the cheapest system for long term use imho. There are a fewfilters that will take care of viruses, but they rated about 50 to 100gallons and have a much higher per gallon cost.

If you both filter and use iodine, you'll take care of ALL water borneorganizms.