Stay limit is 7 days. A permit is needed if you want to guarantee your right to a site, otherwise occupy a site but if someone arrives saying they have a reservation you are required to immediately vacate your occupation of the site. Create an account and sign in to find out site availability and make reservations. No fees. https://www.camplife.com/399/reservation/step1

You do need reservations, they are free just sort of a ain because you must have an account to get the reservation. A link to the website is on campendium.com I am not sure of the actual length of stay allowed, some places say 7 some 14. Florida changed the law a couple of years ago concerning how long and how often you can stay. I believe thete is a limit now on the number of days per year that you can stay in a water management district campground and I don't think it matters which district you are in.