Gas Restrictions on decent

[SoFloDiverDan]

Hey, everyone. Here is something that has been driving me crazy for a little while now. My wife has been experiencing a sensation that she describes as someone closing her tank while she descends. the sensation resolves, after ascending 10 feet up, then she can continue her dive with no issue. This did not start happening until a year into her diving. She has been using an Apeks AT Regulator and an OTS Spectrum FFM. The sensation started after its first service. We brought it back to the shop, thinking the reg was not properly balanced, but it continued after a couple more dives.

So now, here is where it gets even more confusing. It does not happen on every dive, and has not happened on the first dive of the day, nor only after a long period of not diving. We cant seem to replicate the sensation intentionally. We have opened up the second stage to allow the least restrictive air flow, and I have dove with her gear several times with no issue.

We upgraded her to a Apeks MTX-RC Regulator, and had no issues for several months. Until, a dive in Thailand this past January, where she experienced the same sensation.

It has happened in all types of ocean conditions.
She has no feelings of anxiety.
She has logged over 75 dives and is a very competent diver.
She is in normal health, with no conditions or physical barriers.

I feel we have ruled out equipment failure, and anxiety. All I can think is maybe some human error, or something we are missing with the equipment.

Any thoughts?

 

[happy-diver]

decent vs descent - Common Mistakes and Confusing Words in English - Learn English Mistakes

www.learnenglish.de

 

[jeffsky29]

Have you tried switching regs with her when the sensation starts, to see if you experience the same thing? I know you said she does not feel anxious, but seems like an easy safe test to do as you go down the anchor line, to 100% rule out it being in her head rather than in her reg.

 

[happy-diver]

Dude come back, imagine meeting a President with no one having told you you have a booger on your face

 

[Wibble]

Holding her breath?

 

[SoFloDiverDan]

decent vs descent - Common Mistakes and Confusing Words in English - Learn English Mistakes

www.learnenglish.de

If that's my only mistake for typing this up on my phone... not too bad

 

[SoFloDiverDan]

Yea, we swapped regs and both have had no issues using eachother's regs.
I asked about breath holding, and she said it feels like taking a breath through a bent straw when it happens. And resolves with ascending 10 feet or so, then shes fine. She can drop to 100ft like a rock with out an issue.

 

[tridacna]

Have you tried switching regs with her when the sensation starts, to see if you experience the same thing? I know you said she does not feel anxious, but seems like an easy safe test to do as you go down the anchor line, to 100% rule out it being in her head rather than in her reg.

She's wearing a FFM. Not so easy to accomplish. Don't know what the OP is using.

 

[jeffsky29]

She's wearing a FFM. Not so easy to accomplish. Don't know what the OP is using.

I must have missed that pertinent info in the OP’s post. In that case - Nevermind…

 

[Martijn]

Any chance she is breathing through a (older) miflex hose?