Is Bioactive mix (coco coir + sand + topsoil) a Safe Substrate for African Fat-Tailed Geckos?

A well-built bioactive substrate can hold a little natural moisture in one part of the enclosure, which suits fat-tails better than it suits many drier-kept geckos. Keep a clear dry side, add a springtail and isopod clean-up crew, and avoid it for hatchlings and juveniles under about six months.