Yep. Ivan said it all. I think you should try other kind of sand . Garnet or the mixture of black, tan and orange. It'll bring out the "green". Hehe. Forgot. Black sand works too!
I actually just got him. I'm planning to switch to black diamond very soon because my palmas and ornate have become very pale as well. I don't like it! The guy I got him from had him in a cichlid mix substrate, so a good mix of white, black and gray. But I'll see what happens once I switch over to the dark side...er I mean substrate.