The whole sand= impaction is so blown out of proportion is crazy, its misconception and fear that prevents people from using sand witch is a natural, odorless, clean substrate and most importantly........its Safe.
I have been keeping geckos, skinks and my monitor on natural red desert sand for 5 years, not a single case of impaction.
I have on occasion witnessed my monitor get sand in his mouth when feeding on crickets and it passed though him with ease. If your animals are healthy, are having all their needs met in terms of the right food choices (meal and super worms may be ok as an occasional treat but due to their tough exoskeleton they are hard to digest and so not a good staple food) proper heating and a source of water then they will never have an issue.
The private breeder i bought all my reptiles from has been breeding reptiles for 28 years and was a full time reptile and bird vet before that and has sand in all enclosures. How can so many years of experience and knowledge be wrong? it isn't.
One last thing, most reptiles in the wild live on what?......... SAND.
Food for thought-
Thats all ill say on the subject. Cheers-
Darren