For the last two years, I've been using the Aquamira Drops for ultralight backpacking. Drops and iodine tablets are extremely light, cheap, and take minimal effort to use. I love my ceramic MSR pump, but it's heavy, requires constantly cleaning on the trail and takes forever to pump gallons of water. I tried iodine tablets as a replacement, but I couldn't get over the chemical taste. Then I moved on to the Aquamira drops. For 2 ounces, they can filter hundreds of gallons of water. There is no noticeable taste. The drops, mixed together, form an active ingredient that treats water similar to how domestic tap water is treated.