What kind of sand/gravel?
 

Fish I'm planning to keep:
Copperband/Blue Tang
2x False Percular/Tomato Clown
Royal Gamma
Pearly Jaw Fish

Question is mainly for the Jaw fish. What kind of gravel/sand should I use? Or should I use a mixture? I heard that jaw fish doesn't do well in fine sand cuz they can't really dig their tunnels.

I also have a huge bag of gravel from my Fish only days (salt water). The Jaw fish I kept back then seemed to like it at least. Should I use those as the base and just pour live sand on top? Please give me some advice.