I have a bearded dragon who is trying to lay eggs at the moment. In the past we've always used sand in her lay box, but she recently got a lot of sand in her eye and we don't want to risk it again. I was wondering if someone could give me advice on what type of soil to purchase for her lay box substrate. I read somewhere that it should only be plain soil with no fertilizer or anything, but I can't find any products like that in person or online at the moment. I found a product on Amazon called "Exo Terra Plantation Soil" and it looks like it's coconut fiber substrate. Could this be safe to use? Can someone give me some guidance on what to purchase? Thanks.