After reading the thread "Filter v.s. Steripen" it comes through that some folks have not yet been made aware of the EPA water treatment classifications. There are big differences between water filters and water PURIFICATION.
FILTERS > can filter down to one micron but will let some bacteria and all viruses pass through. And yeah, they are heavy and clog. I no longer use filters.
PURIFIERS > will kill (or disable in the case of UV pens) all bacteria and viruses. To date chlorine dioxide - not iodine - is the best chemical treatment. And in that type Katadyn tablets are the most convient to pack and use. Still the EPA will classify idoine based filters like First Need as water purifiers.
GOOD OLD BOILING > Still a great way to purify water, esp. for cooking - and for drinking, if ya don't mind waiting for it to cool.
I now carry the 1st gen. Steripen Adventurer and Katadyn tablets. A small funnel and #1 coffee filters is for all water before treatment. The chlorine dioxide tablets go in my hydration bladder and will keep both bladder and hose bacteria free.
The Steripen Adventurer is for my 3/4 L. bike bottle where I keep my electrolyte drink.
When I need potable water for the bottle I want it NOW, not in 30 mins. to an hour while waiting for a tablet to work.
So far so good, even out west here where wild burros and horses roam all over, including horses high in the mountains (6,000 to 11,000 ft.) just outside of Las Vegas.