Anything Greg and Frank say you can bet it's the most accurate info you will get on scorpions. I'll add a few of my experiences though. First off I would 100% use a sturdy top on the tank, mine was a freak about the lights going off when I had him in a 28 bowfront, he would violently try to jump out of the water. He still does it in the 220 but it's tall enough that by the time he gets to the top there's barely any momentum. The second thing is the substrate, while I'm not at all disagreeing that what you have atm is good, I just have a different preference. I like at least 3" and I use the finest grain I can find, which for me is Bahamas oolite. I like it because he can bury himself extremely easily, and it is also a peace of mind for me because I would worry he might cut himself with the more coarse substrate (even though that probably wouldn't happen). The last thing I'll emphasize is to not put it with any fish that are grazers, they just look too much like a nice rock with tasty algae on it.
Here's my dude
Here you can see how the fine substrate makes him feel nice and cosey
Good luck