Substrate Impaction is the myth that never seems to die. The truth about the impaction issue is more complex than “loose substrate and sand=bad”.
For more information about the subject, I’ll direct you here:
Does Loose Substrate Really Cause Impaction?
Something to note is that out of all of the dragons in the study, there were relatively few impaction cases. This is despite most of the Beardie’s being housed on loose substrate. The few impaction cases occurred in dragons who already had parasites, MBD, obesity and other diseases. No healthy dragon became impacted.
This supports the notion that as long as your husbandry is good and your bearded dragon is healthy, then substrate impaction isn’t something that you should worry about. So a bearded dragon housed on loose substrate will not get impacted if your husbandry is correct.
Also, substrate impaction is considered almost unheard of. Most impaction cases are caused by improper heating or UVB, not substrate choice. For example, Mader’s (The most comprehensive book on reptile medicine)
Plus, there’s a difference between good quality sand and calcium sand. Calcium sand does cause impaction, but that’s only because calcium carbonate acts as an antacid at high doses . Meanwhile, something calcium free such as children’s play sand or sand from the Australian outback is perfectly safe to use. You can actually buy natural sand/soil harvested from the Bearded Dragon’s natural habitat.