a water park and the aquarium sound pretty nice, especially since it's the summer and florida is hotter than a sauna.
does your date like books? take them to the library! chill out for a bit and relish in comfortable silence. (only if they're into that, though. some people find it boring.)
does your date like volunteering? try to look online for volunteer opportunities you two can do together. for example, i plan on volunteering with my boyfriend at a no-kill animal shelter (he loves cats, i love dogs) and the nearby park to tend to its garden.
does your date like cooking? take a cooking class together! i hear those are really cool.
does your date like music? take them to a concert they'd enjoy.
not too hot and looks like a good, sunny day? go on a picnic. pack some lunches and hang out. talk about things and relax! or, if you're feeling up to it, go to the zoo or an amusement park. you're bound to have fun.
i could probably go on and on about this, but you know what i mean. get to know your date and have fun with whatever you two plan! i hope you guys have even more fun next time.