i would try to keep it a bit warmer since it is a florida boxie and they (or so ive heard) are one of the harder ones to keep captively i would think 69 - 70 would be a good night time temp but thats just my opinnion, and i have no experiance with floridas
Check out this site http://www.boxturtlesite.info/ I found it on an older post by someone who said it was a good site. They also said above 65 should be a good night time temp. Howeved i am not sure how moist and humid they keep theirs. You can also pm ( Maggie 3fan) she has boxies. Hopes this helps
I don't like mine to get colder than 60. As soon as it's warmer than 60 at night, mine stay out all night. I even let my yearlings and juvies stay out to the 50s. Hope that helps.