If this was a tortoise for sale, I'd stay away. I suspect MBD.
I've literally spent thousands of dollars on treating MBD in rescuing tortoises and Chameleons. Usually, the treatment only helps with the suffering.
A good set of x rays would determine if it's MBD, but even those are about $80...
I only keep Redfoot. A special species that can eat tons of fruit.
I don't think that a very occasional fruit "treat" will harm other tortoise species. But it shouldn't be fed too often. Also, something like watermelon may cause some temporary diarrhea or otherwise weird dark poop. Its mostly...
They are far more common and far less dangerous than people seem to think.
Especially out of the water and that small.
They'll chase your toy poodle, but not you.
Gator attacks even in water are rare. Deaths caused by attacks are almost not heard of. Single digits. Usually it's some drunk doing...
Redfoot don't produce urates. I think you might be seeing sand and gravel. Is that possible. Dehydration would also be another guess.
(They're BOTH guesses)
Plant shrubs around the edges.
Use giant pots laying on their sides and partially buried.
I only use shade cloth over my fish ponds and that's to control algae.
Redfoot will be active in the early morning and late afternoon. You'd be hard pressed to see one out in the open on a hot afternoon...
These are RED and BLUE. They don't provide a lot of other light.
My Pathos and Sheffleras (spelling?) Did really well with them. And they are cool to the touch.