I agree with you, John. It is a whole new way of shooting. And it takes time to adjust. It is not just a different way of getting colours, but it you have to put images together in a completely different way too, to realise the full potential.
To some extent, you could have lit both your shots with strobes, if you had wanted to, John. Filters become really good when you start producing images that you can't be lit with strobe - not just as an alternative to strobes.
You are using the light well to illuminate the subjects. And a more downward camera angle will get you a better blue. But remember that the foreground subject does not have to be parallel to the lens as to the same extent it does in flash lit shots. Allow the colour to extend back into the shot.

This image would have been difficult with strobes without burning out the sand in the foreground while still getting colour on the corals and diver in the background.
Anyway keep posting them here and I will try and pass on my comments. Otherwise we can do a filter dive when I next see you in Cayman. I am sure others will benefit from the discussion of ideas. That was part of the motivation for putting the Magic out there - to start getting
Alex