True, 30 min to get rid of most of the junk and 4 hrs to kill crypto. I almost bought the UV pen but having read many things about Miox I ended up with it. At first it was still my concern that it takes 4 hrs to completly purify stuff but with the 4 bottle system I had it was all good. Plus since I run kayaking trips with 10 plus people possibility of purifying large quantities of water is a big advantage.