Be careful with the sand, it can cause impaction so use it sparingly. Have you tried orchid bark? Fine grade and most big box stores or nurseries have it. FYI...pine and cedar are toxic to tortoises so avoid anything with them in it...
Am I just missing any lights or heat?
I hate coco coir too. I don't like the long strings that always seem to be hanging out either end of the babies. My substrate of choice is fine grade orchid bark. For baby box turtles I use regular potting soil (the kind that doesn't include perlite) with a thin layer of orchid bark over the top.