If your goal is to be clear and concise - I have seen 1-tank trip/2-tank trip far more often than I have seen 1 dive trip/2 dive trip. Until you put up that 2 dive trip is right next to 1 dive trip, I would have the same question - maybe worded a bit better.
Even then its not clear your site says
Single Dive Trips
Two Dive Trip
One Dive Trip
So one the first line it is Single "Dive Trip"
but on the next line which uses very similar language it is "Two Dive" Trip, see how that is confusing?
Even then its not clear your site says
Single Dive Trips
Two Dive Trip
One Dive Trip
So one the first line it is Single "Dive Trip"
but on the next line which uses very similar language it is "Two Dive" Trip, see how that is confusing?