Hmmm, perhaps the hose is starting to come off a bit somehow (eventhough the hose clamps seem to be in order). Let me feel to see what's going on here.
I feel along my exhalation hose to where it connects to the DSV. Nothing going on. How about pushing the hose on to see if that solves the problem? So, I give this a try. No real change.
Maybe the clamp has worked its way loose or away from the right spot on the hose. After all, it has the HUD on it, and I might have moved it around a bit somehow. No real change.
No gurgling, no problem with anything related to breathing, and I don't see that I am losing gas. Again, it only happens if I pump up the loop enough for there to be pretty significant volume. So, there is no need to do more than finish up my dive normally.
After the dive, I check out all of my gear at home. Everything seems to be fine. No problems with positive or negative check. Could it be . . . the mouthpiece attached to the DSV?
I close the DSV, cover the purge hole (where I can clear water), and I exhale. Sure enough, the hissing noise comes back. Somehow, the tie-wrap has slowly stretched over time enough to allow a small leak to develop. I changed the tie-wrap, tightened up the new one nice and snug, and . . . no leak!
I've never had this happen before on open circuit even with mouthpieces that have been on for years. (I recently switched to the ScubaPro mouthpiece retainers for most of my gear, however, they don't fit this size opening.) Talk about the weird and the strange . . . .
