I know some people like to have one super-sugar bottle and hydrate/refill plain water from their other bottle(s).
This is the hydration pack version of that.
Not for me, but maybe this solves someone’s something something non-problem that I can’t think of. I mean, you could just put 2 bladders in your pack for a fraction of the cost, but then you wouldn’t have a cool dial. So, there’s that going for it.
Oh, I thought it might have in-build recycling.
Feature request! Just don’t pull the wrong lever and reverse the flow. No dial is helping you then, unless it’s to call your past self and ask “where did it all go wrong?”
It could have filtration and be circular.
Maybe for really long rides without water supply? 
it’s interesting that the percentage mix dial has so many options. People are often so specific about their intake needs it’s a little weird to have 88%, 75%, 63%, etc
I’d have to think too hard to adjust it mid ride. I’d almost prefer 2 settings. 100% water. And one other percentage mix so that I would toggle between 2 settings not cycle like 6 settings.
I thought the same. In looking at the site it seems like the settings exist between the off/on settings. i.e. if you wanted just water or just ur carb mix you would flip the switch completely from one side to the other… interesting concept
I really wanted to like this idea when I first saw it, and its just not solving the problem… I hate mixing my carb drinks in my bladder, but its unavoidable at a certain point. I typically have opted for water bottles for mix, and plain water in the bladder. Last week I did another 300 mile ultra, and I simply didn’t need the volume of bottles and a bladder, plus was using a full frame bag, so bottles would’ve required clunky mounting/bags. In the end, I used 2L mixed in my pack, and then a single Fidlock bottle for plain water on the top tube. I actually played around with stacking two separate bladders, a 2L Hydrapak and 1L camelbak, inside of my pack before giving up on that idea. There’s potential there, and I think even if you partially filled each one to get to your desired volume, it would be better than fiddling with a valve(plus the hassle of cleaning it all). It wouldn’t be terrible in use, with say your right drinking tube being water, and left being mix. It really comes down to just craving plain water at some point, but really, if you can get over that, its in your best interest(performance wise) to be consuming calories/carbs as well, so just tough it out with the mix.