tortoise home has a good article on calcium do's and dont's I posted it in anther thread....
I cant find it now... but it was recent...
Laura Morin interesting article on calcium types: http://​www.tortoisetrust.org/​articles/calcium.htm
Tortoise Trust Web - Promoting Proper Bone Development www.tortoisetrust.org
Tortoise Trust Web - A site dedicated to the conservation and captive care of Chelonia