[PSUBS-MAILIST] bellows add

[hank pronk via Personal_Submersibles]

I have been pondering the idea of a bellows add system for Gamma.  I am not sure how the DW deals with pressure change due to temperature change.  When I am diving Gamma the temperature swing is huge causing a big negative pressure inside.  A bellows add system would be dumping O2 in like mad.  Does the DW have an automatic O2 over ride or an automatic air release to compensate. Does the pilot manually add air to avoid O2 build up.
When I surface after a dive without the scrubber or O2 feeding in, I have to open my hatch vent valve for what seems like forever to equalize the sub to open the hatch.  It is getting better with the air temps dropping.  I can't wait to go for a dive when it is snowing. 
Hank