I'm a little confused -- how do you mean that sand will prevent you from seeing them? Is it because of a lack of contrast?
For Vaejovis spp., I'd recommend a mixture of sand and coco fiber. If you're concerned about them not standing out against that, some hobbyists will use black sand.
If your emperor scorpion stops eating, don't panic.
Be nice -- you were a noob once, too
"Never ask an engineer to explain something, because he will."