Yup, RumLad told ya the truth. The warm water in reef tanks shortens the lives of the "Mexican Turbos" considerably. They aren't sold for the aquarium market because they are particularly suitable, but rather because they are easier (and cheaper) to obtain than the warm-water species. The most common cool-water species being sold are Turbo fluctuosus, though some may be Turbo saxosus. Here are links to the ones that don't last very long in warm tanks:
http://www.gastropods.com/2/Shell_2442.html
http://www.gastropods.com/3/Shell_2443.html
The ones that would work better, if you could find them (and tell the difference) are probably Turbo argyrostomus, Turbo chrysostomus, Turbo setosus, Turbo bruneus, and Turbo crassus. These live in the same areas where most of your corals and fish originate. All of them get pretty big, maybe 2 to 4 inches across.
http://www.gastropods.com/4/Shell_1514.html
http://www.gastropods.com/9/Shell_249.html
http://www.gastropods.com/5/Shell_2435.html
http://www.gastropods.com/8/Shell_248.html
http://www.gastropods.com/7/Shell_2437.html
Cheers,
Don