I.m with lowviz here: Breathing air under pressure at depth is "loggable" but log it for what it is- a dive with surface supplied air. SOme activities that divers do are "snuba- including a lot of aquarium work, and Mike Nelson himself did snuba and scuba. If you watch old Sea Hunt episodes (you can find them on line) you will notice the opening intro scene has him gearing up in snuba gear. However, in the actual shows he is on scuba, with little technology we enjoy now, demonstrating how to kick up the bottom, flail around with his hands while swimming, and also quite a few rapid ascents. God love him anyway. Snuba is confining, but is another underwater experience adding to one's resume. Maybe it's best to keep a snuba log separtae from scuba log. But go ahead and log the time.
DivemasterDennis
DivemasterDennis