I'm currently using a mix of coconut fiber, repti bark and some hay as a substrate for my leopard turtles. What do you guys think? Its my first time using this substrate so I'm not sure what to expect :S
Would ditch the hay if your using humidity as this can mould and cause respiratory issues. Not sure about repti bark but i'd just use 100% coconut fibre or sphagnum moss - both hold humidity, dont mould, and dont carry/make bacteria and bugs.
I agree with above. However, I have had the sphagnum moss mold on me back when I first got my tort two years ago. I switched to just coir. However, what up you are using sounds good, except the hay part. BTW, have you read Toms great threads on raising leopards and Sullies? They are at the bottom of my post.