Regarding tank sizes in the Red Sea, my best guess based on personal experience would be that what they call "12L" are, in fact, AL80. This is actually just under 12L.
And their "15L" are AL100.
The latter is notorious for the buoyancy changes as your dive progresses.
And their "15L" are AL100.
The latter is notorious for the buoyancy changes as your dive progresses.