i use . . .
a mix of two subtrates. They are the same but in different sizes, My corn loves this as its all not the same size and he explore with burrowing ect... ect... what i use is one bag of medium sized aspen chips and two bags of small "desert" aspen chips. It looks really cool and as i said, my snake seems to love it. hope this helps!! i attached a pic so you can see what i use . . . lol with my handy webcam, , , i take pics of anything!!! hehehe
KRIS