Night Diver
Guest
Just kidding. I use a 13 when I use a pony, I don't own a 19 so am not qualified to opine on the variations between those two. But this is the thing about ponies, and why there's not a single right answer: you'll lug it here and lug it there, if you're really lucky you'll never use it. If you ever do need to use it, you'll absolutely positively wish it was bigger.
So do you carry the bigger bottle on planes, trains and automobiles (not to mention a hundred or more dives) so that when you need it you have as much as size as possible? It really depends partly on your personality and your dive habits. For me, I figure 13 gets me back to the surface when my primary and second (no octopus here) go kablooie; I won't get in a 5-minute stop but I'll get there at a safe rate. And I'm OK with that risk, others may not be. Seems like a 30-40 would get to be like lugging around a stage bottle; again, depends on how up you are for the extra work.
So do you carry the bigger bottle on planes, trains and automobiles (not to mention a hundred or more dives) so that when you need it you have as much as size as possible? It really depends partly on your personality and your dive habits. For me, I figure 13 gets me back to the surface when my primary and second (no octopus here) go kablooie; I won't get in a 5-minute stop but I'll get there at a safe rate. And I'm OK with that risk, others may not be. Seems like a 30-40 would get to be like lugging around a stage bottle; again, depends on how up you are for the extra work.