I have seen this discussed on an aquaponics forum. Look here - you may have to scroll up to the beginning of the chat.
http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=3198&p=120445&hilit=rabbit+poo#p120445
Congratulations!
The only thing I know about box turtles is that we should not try to re-locate them. They will drive themselves crazy trying to get back to what they consider their home turf. Guess you will have some permanent residents. :D