Rysher, I grew up in Satellite Beach. I know they do water quality testing at the beaches in front of Patrick, might want to google those and see what they come up with in parameters. If you want to get water, you'd probably be better off getting it from Sebastian inlet, which sees tremendous current and water exchange every day.
alinity you really want to be around 1.024-1.026 for a reef aquarium so you could always dilute accordingly. Be careful though, with the cruise terminal there and so much history of military activity, who knows what's in that beach water. (not that it matters, I grew up going to second light nearly every other day during the summers and I'm still alive)