You could use this sand but remember there are a lot of people, boats and industry right there - When they talk about Florida Keys Live sand they usually get the sand about 1-3 miles off shore.
I have heard of many folks on this site using beach sand sucessfully - just be aware of the pollutants mentioned above.
You might want to take the sand from the beach and boil it/sift it/bleach it for your base sand and get about 40lbs of Live Sand to put on top.
That would be real cheap.