Underwater Effect

[Tom Bottiglieri]

I am doing a project for school in which i need to create a new book cover to the book "The Pearl". Most people are just drawing theirs, but I wanted to do it in 3dsm. I have my entire underwater scene modeled out, but now i am trying to add an underwater effect to it. I was thinking of just making a plane that is offset to the ground, giving it a water colored shell and setting the opacity so you can see through it. I tried that, but it hasnt seemed to work yet. Either I just get some weird blue streaks going though it, or it looks like the actual sand is blue.

Has anyone ever done anything like this before, and if so, how would I go about doing this?