Hi and welcome, If you post this on the main forum introduction or in the Health section you will get a lot of responses and the help and advice you need for your tort. Not everyone reads the profile posts.
If you include pictures of him and his enclosure that will also be very helpful
Have you had him since he was a hatchling?
There is a great caresheet for sullies in the species section too.
I was just asking because they do burrow if they get too hot or for shelter at night so wondered if you'd seen him doing it before. The soil would be normal I think, but I don't know about the bubbles.
There are lots of sully keepers on the forum though so they'll help and could save you some money on a vet.
If you include pictures of him and his enclosure that will also be very helpful
Have you had him since he was a hatchling?
There is a great caresheet for sullies in the species section too.