Sand as a substrate ??

[Beardedragon]

Redtailed boas don't live on sand in the wild. Repti-sand is a bit better than normal sand but I still don't trust it. It's very dusty and if ingested can still cause problems. Plus they don't burrow deep so there's really no need.
A boa would be much more comfortable on aspen enough to burrow slightly. Good for you for checking with us instead of trusting the petstore guy! I've never heard of repti-sand being able to absorb nutrients through the skin because that doesn't make a whole lot of sense.. it has nutrients in it for geckos when they eat it with crickets but thats all I know about the stuff.

Trust me, its not fit to house a stuffed animal. Pet store bought sand is never any good.