Upside down breathing with apeks reg

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seabass

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I have an ATX 100 and have been trying to practice buoyancy control upside down. (There isn't much else to do in lake travis). The problem is that my ATX 100 doesn't breathe well at all while upside down. Have other people people found this to be the case?
 
That's kinda bizarre... my TX40 does fine upside down.

There was another thread about this.. does the ATX series have a problem with this in general?
 
TX 50 is pretty good when contorted in all manner of positions, trying to grab Crayfish.
Gets a little wet occasionally, but nothing to worry about.

Dave
 
Have you thought about switching regs?
 
they don't breath as well upside down. It's a fact. My TX 50s don't either.

Tom
 
Tom,
Doesnt breath AS well, or doesnt breathe well AT ALL?

Mine has a differance, but not problematic, Sea bass is saying his doesnt breathe well at all!!!

Dave
 
My TX50 doesn't breathe WELL upside down, but still breathes quite manageably. Does get a little wet from time to time as well.

SS
 
Try as we might, we just can't avoid that pesky physics. When you cut away all the fancy pieces, it all boils down to this... During normal operation, all mechanically actuated underwater demand regulators require displacement of a diaphragm to open the valve that provides air. In scuba, the regulator is tuned so that this diaphragm moves effortlessly in a normal swimming position. On the "hockey puck" style regs (includes Apeks) this is with the diaphragm slightly lower than the mouthpiece, so there's the tiniest little bit of water pressure already on it. When you turn it "upside down" you're positioning the diaphragm above the mouthpiece, and now you have a "bubble" under the diaphragm - the pressure differential has been reversed, and you now have to overcome that half inch or so of water pressure before the diaphragm can move and open the valve to provide air. It's the same reason you can usually stop a regulator freeflow by simply turning the mouthpiece down.
Attempts to overcome this have been made by placing the diaphragm to the side (Poseidon, for example) rather than the front of the reg, and that works - but - now you've just moved the "hard to breathe" position from "upside down" to "on your right side."
So what you're experiencing is "normal operation" - irritating to many, with a little experience it'll be something you learn to expect, compensate for and eventually you won't even notice it.
As for wet breathing, that's another matter and has to do with the placement of the exhaust valves. These are positioned at the "normal" low point in the reg, so any water that gets into the reg is exhausted with your exhaled breath. When you turn upside down for any length of time, water can accumulate since the exhaust valve(s) is no longer at the low point, and you either need to get it there for one exhalation or do a brief purge or forceful exhalation to displace enough of the the water upwards to where the exhaust valve is now located to make breathing "reasonably dry" again.
Rick
 
Aquamaniac once bubbled...
Tom,
Doesnt breath AS well, or doesnt breathe well AT ALL?

Mine has a differance, but not problematic, Sea bass is saying his doesnt breathe well at all!!!

Dave

Well, it still breathes but there's a noticable difference. I really don't notice it being wet as some have said but it breathes noticably harder.

Tom
 
I have a couple of observations on the issue of 'difficult upside down breathing':

I dive Poseidon Odins (side exhaust) and Mares MR16 Voltrex and Mares Ruby (conventional exhaust) and they behave similiarly as follows:

If by 'upside-down' you mean you are horizontal in the water (on your back) looking straight up.......(or just vertical in the water, feet downward, stretching your neck and leaning your head way back to look straight up)...... then yes, I've noticed a bit more breathing resistance in that position, it's not realy severe, but it is noticable. This it true for both the side-exhaust and the conventional exhaust regulators.

On the other hand, if by 'upside-down' you mean you are vertical in the water, with your feet straight up and your head straight down......or just in any position where your feet are somewhat higher than your head.......then I've noticed that both the Odin and the Voltrex breathe a LOT EASIER in that position.......it's the easiest breathing position for both regulators.

As far as wetness goes......both the Odin and the Mares Voltrex/Ruby are BONE-DRY in every conceivable position......and I've done deliberate experimenting to try to find a position where I can get water to enter the 2nd stage......I've never managed to get any water into the 2nd stages.

Karl
 

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