The website seems to contradict itself:
Red-eared sliders are a common non-native turtle that has been popular in the pet trade. Red-eared sliders are listed as a conditional species in Florida. Anyone that possessed a pet red-eared slider before July 1, 2007 can legally keep their turtle and no permit is required. However, Floridians are not allowed to acquire red-eared sliders as personal pets after that date.
Anyone importing or possessing red-eared sliders for research, exhibition, or out of state sale is required to have a Conditional/Prohibited/Nonnative Species Permit. Certified aquaculturists with restricted species authorization from the Department of Agriculture and Consumer Services may possess and cultivate red-eared sliders for out of state sale and for sale to permitted Florida researchers, exhibitors or dealers, or to other certified aquaculturists. Authorized aquaculturists that import red-eared sliders also must obtain a special permit.
Trachemys scripta elegans (Red-eared slider)
A permit is required to acquire red-eared sliders for personal possession; red-eared sliders must be contained in outdoor facilities that have a permanent containment barrier secured at least six inches below ground level to prevent escape by digging, erosion, climbing or by passing through gaps; such barriers may be constructed of solid metal or weather-resistant and rot-resistant material, and may not use mesh material. All eggs must be removed and destroyed daily from outdoor facilities.
Red-eared sliders in personal possession prior to July 1, 07 may continue in the possession of the owner
Red-eared sliders less than four inches carapace length may not be possessed after July 1, 08 without a permit
Red-eared sliders with distinctive aberrant color patterns, including albino or amelanistic specimens, may be possessed without a permit otherwise required by the rule