I went to Antigua in January ... and put together a brief video with a combination of both stills and video from the trip.
Link to Antigua Underwater Video
My rig was a G9 in the OEM case with two strobes (YS-27 & YS-15) and a Fantasea Nano focus light.
Most of the time I had a Magic Filter over the lens so I could shoot both color-corrected video as well as use the strobes for most stills. I was able to get a perfectly acceptable white balace shooting with strobes and magic filters as long as I manually white balanced with the strobes firing and the filter on.
Enjoy!
I'm going to Mexico in June and hope to shoot a lot of video in the cenotes when I go, but will probably leave the magic filter behind to capture the natural colorscape ... I'm debating whether to buy the Ikelite case so as to have a wide-angle option ... or go crazy and make a DIY short-port out of a second OEM case ... seems a bit daunting.
P.S.
If you want to amuse yourself, check out this silly little video I put together ... Dancing Bears ...