That's what I'm talking about!! See, you only needed to move the light and throw some sticks in there and you've got yourself a deeper [appearing] tank!
Everything will look a little different once the tank is full of water, obviously, so keep in mind that you may need a second or stronger light in the shadow box to allow the shadows to penetrate through the tank while competing with the tank's lights reflection off the back wall of the tank.
I'd suggest filling up the tank and turn on the tank light to see if you really need to add another LED strip in the back or not. You'll be the judge of that since pictures never do shadowboxes justice in person. Maybe even angle the strip towards the back of the shadow box, if you can, so you keep the light from directly reflecting off the glass.
Another thought: I'd personally make the back of the shadowbox taller, that way the LED is "out of the water" in the back so you don't get those spotlight effects. I'll see if I can explain it: make it about an inch taller than the back glass, and put the LED where you currently have it. Obviously, there will be an opening between the top of the box and the top of the tank that will allow the light to escape -- tape or glue a strip of the foamboard in that gap, so you basically have a "step" in the back of the tank from the top of the tank to the top of the box. That way, the light is above the surface of the water, and also so you still get to hide the LED strip in the box.
Last edited by ngrubich; 11-11-2014 at 01:43 AM.
Reason: extra info