For not particular reason I’m not a fan of “the hydration pack”. First of all they are expensive relative to the smartwater bottle. Second they are not as ubiquitous as the smartwater bottle And third but not last the bottle works great with most water filters. And let’s not forget the first purchase includes water for free.And so I implemented a DIY smartwater hydration project. I particularly like this project because my Yukon Outfitters El Capitan pack has deep web pockets, smaller bottle has a spoutStep 1: buy a smartwater 1L and .8L bottlesNotice that not all the water bottles have the spout. The spout is required for this project but not in general. This project is only part of my water system which includes my sawyer filter. An original spout or syringe is required to flush the filterthe spout removed from the bottleStep 2: remove the spout from the bottle.Step 3: the original opening is not actually wide enough for the tube so hollow it out just a little.Step 4: remove the lid from the spoutStep 5: measure the tube against the 1L bottle to get an approximate position for the spoutStep 6: run the tube through the modified spout and superglue it into positionStep 7: (not pictured) install the mouth piece to the other end of the tubeInstalled on haversack - this pack has shallow web pockets and no place to secure the tube on the shoulder harness. Notice I used some green/black shock cord. (bottom right)Installed on Yukon El Capitan there is a built-in green restraint on the shoulder harness.The best part about this project is that I do not have to clean the hydration bag. Just replace the bottle as you would normally. This could prevent some nasty side effects although you still have to clean or replace the tube and mouth but this can be done with a sterile wipe or boiling water (this will fit in a stanley pot).