>I'm not sure that you would save time with a gravity filter...I think that the most efficient method would be to use klearwater and a spare two liter platypus reservoir
That's why I'm using a UV Aquastar sterilizer. By zapping the water (1.5 minutes per liter, drinkable immediately) as needed, I'm carrying the UV Aquastar at 3.5 oz (including battery) but _not_ carrying 2.2 pounds per liter of water for 30 minutes at a time, or longer. Quite a weight and time savings.
The UV Aquastar kills protozoans, cysts, bacteria and viruses, and maybe doesn't kill tapeworms. Fortunately, tapeworms and their eggs should be easily filterable with a paper coffee filter. (Does anybody know if Aqua Mira kills hydatid tapeworms?)