See what happens to the DM at the 20sec mark on this video...
[video=youtube;dmG0SzvCTQ8]https://www.youtube.com/watch?v=dmG0SzvCTQ8[/video]
Buoyancy control has precious little to do with Galapagos diving.
But did you notice - he was wearing split fins ! Phil.
Sorry - and also just noticed someone else said this.
But seriously I would wait and dive Galapagos when you are a bit more experienced and comfortable with unpredictable currents and suchlike.
I dive half a dozen or so times a month in Cyprus light wetsuit and it is really like a big swimming pool - warm, very little current and good visibility.
I then dive three or four times a month in a uk quarry - drysuit, cold, dark and visibility often less that a couple of feet. Maybe half a dozen or so times a year I dive the English channel off Portsmouth. Very different kettle of fish. Tides, with a tidal range of 9-12 foot sometimes, currents that reverse every few hours with the tide, and can sometimes be 1-2 knots - you can't swim in that for long.
So you have to time your dive for slack water, and that might still have a strong current. I have made dives where I have had to hold onto the wreck and pull myself back to the line hand over hand to avoid being swept away - and that was on slack water !
I always have to make sure I have mentally prepared myself for the change in diving conditions and greater challenges or I don't enjoy the channel dives.
So, nice as diving Galapagos sounds, I would try to get some experience in different conditions and make sure you are really comfortable in them before tackling that.
If you are UK based then I would seriously recommend finding an active dive club, most BSAC clubs are quite good. Get out and dive a few UK sites with tides and currents, get UK sea diving cracked and you will be ready for Galapagos.
Dive safe and have fun - Phil.