Sand can be very dusty as well. I think there should always be trials when raising a captive animal. I am going to use bed-a-beast and see how things go. For now, I am using sand and I always see him shaking the sand off his face. It especially gets in its eyes. And like the previous post mentioned, coconut coir is loose and fine, something I am 'hoping' for so when I remove and handle my uro away from his enclosure, the substrate won't fall unto the carpet.