ppO2 warning and mountain lake

[Marty]

Hello, I've the folloing situation and don't know why?


I am diving in a mountain lake - ~8 h after arriving @ ~1100 meters
It was a quite nice, 50 min, max 10 meters dive
after arriving at 3 meters and after safety stop I slowly ascended - very slowly.

at the surface I got a warning by my OSTC3: ppO2 warning 0.18?!

I tried to do the safety stop at 2 meters again. at 1 Meter the warning disappeared but also after another 2 min at the surface I got the same warning.

Anybody has an idea why this happens? Is it simply the min ppO2 warning and is this also the way to fix i?

[Arno]

When you get to 1100 meters, atmospheric pressure will be about 0,88 bar (whereas it will be close to 1 bar at sea level.
When you dive with normal air (20,9% oxygen), the partial pressure will get very close to 0,18 (0,88 * 0,209).
Small fluctations in the pressure can give the warning...

[sailor]

And this warning has nothing to do with decompression or safety stop.
I believe the warning will disappear once the computer switches from dive-mode to surface-mode.

[Thomas]

Hi Marty,y

I experience the same as I'm quite often at higher lakes diving. Other computers with air pressure sensors have the same issue if you want to call it an issue.
It's exactly like sailor mentioned. The warning will dissabear with switching to surface mode.

BR
Thomas

[heinrichsweikamp]

Well, it's a ppO2 low warning. And your ppO2 is low. So the computer warns. With all warnings in the OSTC: It's only a warning. You can ignore it if you want to.

Regards,
Matthias

[sailor]

Or you can use e.g. NX32.