What's the trick to getting the O-Ring out of the body of a snorkel? Clearly the touchdown tube needs to come out, but the O-Ring holds the tube in, right? Trying to force it past the gasket seems like a royally bad idea. Does the blind cap come off the tube somehow, or some such thing?

Nevermind, flathead screwdriver up in to the tube, screw holds the blind cap on to the tube. Lesson learned.