Long, Long, Ago, in an age not too far off, I was hiking with the boys in West Texas. Summer or Winter that means lots of water. We watered more then frequently and in those days we were treating wild water with Iodine tabs. The water bladders did not last as long as they do now days and one of the boys ran his water bladder tube through the top of a 3L Soda Bottle. Although bulky he managed to secure it inside his frame pack without difficulty. It turned out that his rig was the easiest to refill, clean, treat, and replace, of all the canteens we had. Just a thought...