K valve, Jim T, like Captain I generally do not use all of the redundancy. When the reason exists for me to use it I do but that is fairly rare. I don't buy into the two of everything rule, I have explained this before, robust and reliable and simple systems are my answer to having plastic fantastic failure prone and maintenance intensive gear. Also not relying upon gear but instead experiance to get me out of a jamb. It is simply another vantage point to the same end. My head is hurting now, perhaps later Iwill give a better explanation. I don't solo dive overhead or deco and generally below 60 to 100 feet dependent upon various factors I do carry a pony or other dual system. Esentially I think redundancy as used by many is not solving anything and may actualy increase chances for failure.
In the case of myself and Captain at least this is not all hypothetical, this is how we dive and how we have done it for many years.
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