Quote Originally Posted by pdoege
Pardon my ignorance, but are you talking about the crazy little line that branches off of the lips bypass? I've often wondered where that thing goes but even with my tiny back mount tanks I can't even think of following it.
Yes, that's the one.

Even if you followed it you wouldn't get far that way in backmount. After it turns it goes through a squirrelly crack I wasn't sure my sidemount tanks would fit through until I tried it - and then verified I could get back out.