I agree with Peach. They will get used to you and come see you when you come up to the cage sometimes. Mine will eat when ever food is in the tank. I have a 55g tank with sand and caves, like you said you wanted. They love it, its cool have alot of leo's in one tank, its like watching an ant farm(thats the tank with my male and his ladies). I use sand called Calci Sand or Vet Sand. Its just Calcium that is colored. So if they eat it, its all ok and even good for them. My female is a cluts and will grab a mouth full of the sand and thats great for her egg development.
Good luck, you would love a leo, they are very night active and even day active if you play your cards right with the food. 

Austin
2.3.3
