Air venting from mask during inhalation

[jepuskar]

After a ~2 year hiatus from diving I went to the local quarry and did a 90 minute dive to start to freshin up for an upcoming trip. About 60-70 minutes into the dive I started experiencing this...

As I was inhaling, air would vent from my mask. I'm not talking a little bit, but a lot. To the point where my mask was shaking. I thought to myself, ok...this is annoying. Where could this air be coming from...the only logical guess was my nose. :blinking:

After a minute or two of this I pressed my mask tight against my face. As I inhaled I watched and felt the mask fill with air and then vent. I'm thinking the reg is delivering more air than is needed and it's coming out my nose...kind of like an overpressure situation. I have a ScubaPro with an adjustable knob for air flow. I can't remember now if I fiddled with it or not as this was happening, but I did tighten my mask straps a little and the problem seemed to go away the rest of the dive.

Thoughts from the gallery?

1) I've never done any illegal drugs. Only prescription and OTC.
2) It was happening on inhalation, not exhalation.
3) I wear a BP/W.

Turns out, I have posted about this before...about 8 years ago. http://www.scubaboard.com/forums/ma...-air-exhaling-out-nose-during-inhalation.html



Thanks,

Jason

 

[g1138]

Your adjustment knob controls inhalation effort. How hard you have to inhale to get air to start flowing, or how hard you have to inhale to reach the cracking pressure. Dialing it would most likely do nothing to solve the issue. Preferably you should loosen it up until the point where it just starts to free flow underwater, then tighten it right until it stops. This prevents premature wear and tear.
Looking at the dial as if it were a clock face, dial it counter-clockwise to loosen (lefty loosey)

If your regulator has a pre-dive/Venturi switch, try toggling that to OFF or pre-dive. That might keep air from continuously rushing out in excess.

Other than that you can try some exercises on separating control over your epiglottis and soft palate. Your soft palate is the valve between your nose and your throat. If you have trouble with no mask swims, then I wouldn't be surprised with this nose leak coupled with an easy air delivering reg.

Your soft palate closes up from your throat, so if air is leaking from your mouth out your nose and you're not feeling a jolt in the upper back of your mouth when inhaling, then I suspect your soft palate is wide open. So in that sense, had you had no mask, you'd be breathing from your nose and your mouth.

Onto the exercise:
Hold your hand over your mouth to block air flow. Breath out through your mouth to puff up your cheeks. You should be holding the air from escaping, but none should be coming from your nose.
Very quickly release your hand and air should come rushing out immediately. If it does not then you were closing your epiglottis (located between your mouth and lungs; ie. holding your breath)

Repeat if successful but this time keep your hand over your mouth and release the air from your nose. You should feel a jolt behind and above your uvula (the dangling thing at the back of your mouth). That jolt is air rushing past your soft palate, but in the opposite direction of how it closes (hence the jolt).

Repeat again if successful but this time continue doing so, swapping your releases between your mouth and nose.

 

[jepuskar]

You are a knowledgeable individual. I will experiment again and write a daily report.

 

[captain]

It mostly depends on the fit and tightness of the mask. I has happened to me with a particular mask but not with others. The regulator has nothing to do with it.