sand as substrate for pacman

[diabolique]

hey everyone,
i am planning on changing the substrate in my pacman frog cage to mostly dirt with a water dish. When i was at the vancouver aquarium I saw there pacman frog in a mixture of mostly sand and dirt (like 90/10). Would this be better than straight dirt? Cause i kinda like the way the sand looks?

please let me know i would like to redo his cage soon.

thanks
d