Unfortunately Grand Turk was hit directly by two major hurricanes in the 2008 season, Hana & Ike, which devastated the island, and washed literally tons of debrie into the water and onto the reefs. The island was without electricity for more than 6 months. It’s been a few years since I’ve been there, which was a couple of years after the hurricanes, but the diving was not particularly that good. Maybe it’s recovered, but I doubt it’s better diving than that in Cozumel!