I remember my computer reading 49 minutes when we stopped to film the sea lions. My tank was at about 1700 psi and I was going to signal to return, but went ahead and burned another 200 psi to film. I figured a longer surface swim if, I ran low on air further out along the wall than usual, was worth it. When I turned on my air to rinse my regs that afternoon the gauge showed 250 psi! I hope Anywater doesn't insist on doing a visual when I get it filled.
We covered a lot of ground but it was at a very slow pace, stopping frequently to film, so didn't affect our air consumption. We'd discussed staying at 20feet, but with the surge and currents both just decided to cruise a little deeper.
One interesting sight on the return was seeing a wall of sandy water approaching and enveloping us, reducing the vis from 30+ feet to 15 to 20.