topher10
Contributor
EDIT: Typos in the original post have been corrected. My apologies. EDIT
I recently did a nitrox dive using 36% with the sand at 95ft. Therefore, no chance of going past PO2 = 1.4. However, right at the beginning of the dive, at around 85 ft, I realize my computer is beeping, and it says UP. I head up a few feet and the computer reverts to normal. A few minutes later, again around 85 ft, the computer alarms again, and again I go up and it reverts. Most of the dive is spent at 70 ft, but at times I go lower to see stuff. Over the course of the dive I decide that it is alarming somewhere around 80ft, and I assume this must be an early warning related to PO2, perhaps 1.2 or 1.3.
Now that I am home I know that with a 36% mix PO2 = 1.2 at 77ft, and that my computer (in NORM mode) gives a warning at 1.2 and then an alarm at 1.4. So every time I crossed 77 ft it was warning me, even though I was well away from 1.4.
My question is: Is this 1.2 warning appropriate, or something to be concerned about?
I feel that I have 3 options:
1. Always use a mix that stays above 1.2. For instance, I would have no alarms on this dive with 32% instead of 36%. However, I am losing some of the benefits of Nitrox by doing this, essentially adding an additional safety layer and never diving past 1.2.
2. Just deal with the alarm but avoid going to 1.4. I can silence it and it just says up, while still giving depth. But I am not sure this is ideal.
3. Swap to Tech mode and set the PO2 alarms myself. Perhaps the warning becomes 1.4 and the alarm becomes 1.5 or 1.6.
Thanks for any thoughts/advice.
I recently did a nitrox dive using 36% with the sand at 95ft. Therefore, no chance of going past PO2 = 1.4. However, right at the beginning of the dive, at around 85 ft, I realize my computer is beeping, and it says UP. I head up a few feet and the computer reverts to normal. A few minutes later, again around 85 ft, the computer alarms again, and again I go up and it reverts. Most of the dive is spent at 70 ft, but at times I go lower to see stuff. Over the course of the dive I decide that it is alarming somewhere around 80ft, and I assume this must be an early warning related to PO2, perhaps 1.2 or 1.3.
Now that I am home I know that with a 36% mix PO2 = 1.2 at 77ft, and that my computer (in NORM mode) gives a warning at 1.2 and then an alarm at 1.4. So every time I crossed 77 ft it was warning me, even though I was well away from 1.4.
My question is: Is this 1.2 warning appropriate, or something to be concerned about?
I feel that I have 3 options:
1. Always use a mix that stays above 1.2. For instance, I would have no alarms on this dive with 32% instead of 36%. However, I am losing some of the benefits of Nitrox by doing this, essentially adding an additional safety layer and never diving past 1.2.
2. Just deal with the alarm but avoid going to 1.4. I can silence it and it just says up, while still giving depth. But I am not sure this is ideal.
3. Swap to Tech mode and set the PO2 alarms myself. Perhaps the warning becomes 1.4 and the alarm becomes 1.5 or 1.6.
Thanks for any thoughts/advice.