Sounds like time for testing. First at home in a dark room then at the pool. You do not want another unsatisfactory trip experience. You thought your old settings would work. Now you have new settings you think will work. Time for proof in action.
TTL is nice for macro but manual is sometimes better. Wide angle is often better in manual. You want to know how to set up your system both ways and have the demonstrated proof before you head out on a trip.
You can test your rig in a dark room, large enough to need full power then get close to things where you need less power. Both in TTL and manual. You should have settings that work for both. Once mastered, to the pool to demonstrate it underwater.
That is what I did when I was first setting up my rig.
Just a thought...