@50centipede First, I do not believe that sand is any danger to your animal. However, it doesn’t provide a stable medium for them to make scrapes or burrows. I keep a variety of desert scorpions, and use the above stated mix of sand and topsoil. @Ciri pointed out someone who uses straight sand. Just because someone does something, and it works, doesn’t mean it can’t be done better. I see a lot of stuff on YT that makes me cringe, so that’s not the end all be all of propriety. Additionally, there are different kinds of sand. What is pictured above appears to be relatively large grain beach sand. I use much finer grain sand with the topsoil.
@FrDoc That's a very valid point you raise, if it is a fine sand then you're right they won't be able to burrow persay, they end up just digging a sand pit. For my baby androctonus crassicauda I use a fine white quartz sand, partly for aesthetics but also because I fear anything that can hold onto humidity might cause it harm in the long term.
As far as I know, some species such as androctonus can end up with a fungal infection so it's best to err on the side of caution for desert species.
If using straight sand, putting many nice cork bark hides around the enclosure can make it very accommodating for a desert species
I suppose in all authenticity, a soil and sand mixture would be a welcome addition to a desert scorpling and you'd probably see burrowing thermoregulation behaviours you wouldn't otherwise see using a fine sand. See this is why I treasure Arachnoboards because there are many mysteries in optimally keeping species and we get to have these discussions!