I have been having a bit of trouble with my PO2 monitoring with the 4th cell and VR3 when manually adding O2. I nearly always fly my Meg with a slightly lower setpoint to what I want and manually add O2 to maintain my PO2. I don't have to anticipate the solenoid firing O2 and I can maintain much better neutral buoyancy, specially when diving in a wreck where it's paramount to have perfect trim.

Having the 4th cell and the manual add valve both located in the inhale CL causes it to spike my PO2 readings on the VR3 and causes it to have a heart attack. Lately I have been changing it to monitor a preset setpoint and not worry about the 4th cell monitoring, but it defeats the point in having the 4th cell at all.

I have been thinking of moving my O2 manual add hose to the Mixed Gas Bypass and manually add O2 into the exhale CL. This seems to make sense to me as the O2 would have time to better mix with the gas in the loop and would pass the cells in the head before passing the 4th cell and then being inhaled.

Has anyone already tried this and got any feedback before I try it for myself?

Regards,

Lance