OK, so I'm back to square one. Last year, I devised my own gravity filter system using a Platy 3-liter hydration reservoir, some Platy tubing, the Frontier Pro, and some tablets (Jason Klass' system is pretty much the same). The downsides to the system were as follows:
1) The wait time for the tablets to work prior to the filtration was really annoying. (Remember, the Frontier Pro only filters protozoa, not bacteria. Need the chemicals to kill the baddies).
2) The limited volume of my 3 liter Platy hydration reservoir aggravated problem #1, meaning I would have to run more than one batch when hiking with a partner, doubling the wait time. Furthermore, the small opening of the Platy reservoirs means they are a pain to fill. (Yeah, you can use a cut off water bottle, but it is still somewhat inconvenient).
3) Worst of all, the system was rather slow. The Frontier Pro filter (probably due to the carbon element) took forever to filter.
As a result of these problems during intially testing on an overnight trip, I ditched the whole system and decided to go with my trusty Sweetwater filter, which weighs in around a hefty 11 or 12 oz. I found that the quickness and ease with which I could filter from the ever present streams in the Colorado Rockies made up for the extra weight. I found that the weight was compensated by the less water I was carrying between refill points.
My conclusion: A fast and convenient pump filter system, while heavier, works better in an environment where water is plentiful and you are resupplying perhaps every couple miles. If you're hiking in a desert environment where refilling is sporadic, then yes a gravity filter, albeit slow, is your best bet. (However, after a trip in Big Bend over the winter in which I had lug gallons of water, I have sworn to eschew desert hiking altogether).
Now I'm back to square one. I am still trying to find a way to ditch my heavy pump filter. Yesterday, I finally got a chance to inspect the Platypus Clean Stream system at REI up close. I like the fact that the dirty bag has a 4L capacity and a shut-off valve. Huge plus. I like the fact that it filters 4L in 2.5 minutes (per the advertising). I dislike the fact that the filter cartridge is unnecessarily heavy and that the system includes extraneous items (i.e., the "clean" bag).
The Sawyer inline filter caught my eye at REI as well. At 1.8 oz, it seems like a winner. It also filters out 99.999% of all baddies (except viruses) just like the Clean Stream does. I am now thinking about buying the CleanStream "dirty" bag and hooking it up to the Sawyer.
What do you guys think? Will the Sawyer produce water that is just as fresh tasting as the Clean Stream? They both appear to utilize the same hollow fiber technology.
Ben Tang, are you still around? Tony?
Thanks guys for reading this long post.