Quote: (Originally Posted by
Hk101gr)
Hi andy,
I believe that an oxtox from a single breath of pure O2 even at considerable depth is highly unlikely. One breath just isn't enough for the gas to diffuse into your body in sufficient quantities. I agree it can't be good though.
Consider also that when flying manualy at depth (i've never flown manually to the depth you mention) you need a very slight push of the button to add a sufficient quantity of O2, i don't think it's anywhere close to a lungfull or even half.
Dive safe
Dimitris
I had a lot of trouble with the 4th cell/VR3 option when manual adding in the inhale CL. That is because the cell is in very close proximity to the manual add valve. The continual O2 spiking on the VR3 led me to simply remove the O2 hose from the inhale CL and connect it to the exhale CL (MGBP)
It kept the PO2 aligned a lot better and also gave the O2 more time to homogenize with the gas in the loop and pass the cells in the head before being inhaled therefore giving a more accurate reading of the inspired gas. This at the time seemed to be the best solution.
Then I got to thinking why Leon had put it where it is........and that is, in the event that the diver finds the loop has become hypoxic and needs O2 fast it's right there. The other reason for putting it back was that if anything were ever to happen to me and another diver was to rescue me and wanted to manually add O2 into my loop he would have to work out where the hell the manual addition was.
I fly my unit manually 99% of the time and only rely on the electronics as a backup in the event I get distracted or my workload is higher than normal. It's really very easy...The deeper you go the less time you need to hold the valve open. I haven't had any issues shallow or at depth and your batteries last heaps longer.
Regards,
Lance