No, you shouldn't premix a trips-worth of Aqua Mira. But it's incredibly simple to mix in the field. Heck, if I can do it without spilling everywhere... <img src="/forums/images/graemlins/crazy.gif" alt="" /> I carry AM and one of those little in-bottle filters (and one Nalgene to use it with). AM is primary treatment, the little filter's only if I run into a really yucky source I can't look at much less drink.