Laurie: I am located in Illinois, however I did do some research on salt-tolerant turfgrass species for Florida. From my research, it appears that Seashore Paspalum grass would be your best choice. This grass thrives in saline areas and has excellent salt tolerance. The University of Florida web site has an excellent publication on Seashore Paspalum. It explains how to establish, maintain and care for this grass, as well as its advantages and disadvantages. The URL for this site is: http://edis.ifas.ufl.edu/EP059
Another UF publication titled "Selecting a Turfgrass for Florida Lawns", has a table that shows the different turfgrass species of Florida and their tolerance to salt. Its URL is: http://edis.ifas.ufl.edu/LH005
In addition, your local UF Extension office is located in Key West. The following was on their web site, "During the upcoming year the Monroe County Extension Service Horticulture staff will be holding a series of workshops throughout the Keys on “How to create and maintain a Florida Keys Friendly Yard”. You can call the Extension Office at 305-292-4501, visit our website: http://Monroe.ifas.ufl.edu
or email us at Monroe@mail.ifas.ufl.edu to receive more information about the Florida Yards and Neighborhood program or upcoming workshops. Contact Kim Gabel, Environmental Horticulture Agent, at your local Monroe County Extension office for more in depth information. I hope you find this information be useful and if I can be any further assistance, please contact me.