Yes Mike, proper venting happens easily with a nice, loose OPV, aided by pushing down on the CLs with one's hands and the occasional nose vent. My AP buddies all complain about the super tight stock OPVs and how they only activate by pulling on the dump cord, a design feature which may help facilitate pressure tests on the surface, but which certainly isn't convenient in the water, either during a slow ascent or even potentially injurious during a fast, emergency ascent. And why is the OPV nearer to the bottom of the CL? A great feature, if you dive upside down and like pulling on a string.

None of my 5 AP buddies used the OPV and vented through their noses or around their mouth seals, which I try to minimize as I don't like messing with my mask seal too much or letting any water into the loop through the DSV.

Never had a problem keeping min loop volume and high SP on ascent.

What exactly is the point of having an ECCR, if you're not going to let it help with solenoid injects on ascent, when O2 addition happens most frequently and when you need the most help keeping up a falling PO2?


In answer to the original question: IMHO, SP change to low at 5M, above your last stop and change to high at 5M, as during a descent, the dil gas coming from the ADV filling the loop should slow the injects as you descend and minimize overshoot. The only times I've had any notable overshoot was when I have paused for a while during a descent. If one were to use a rich dil targeted to the max depth, overshoot will be even less, even if you pause during descent, which is another argument for richer dils...