My background idea is starting to take shape. I found an awesome airbrush expert thanks to Logiq. I am thinking right now that I make a small shadowbox, 4'x2'x2" only a couple of inches deep, put hardboard on the back, airbrushed with rock on it, with smooth hazy edging to the rock. Then on the front of my box will be a sheet of frosted blue acrylic, maybe buffed up with fine steel wool to be hazy. Then I put a strip of LED blue and whites on the top of the box shining down between the acrylic and the hardboard. Attach to the back of my tank, and it will give the perception that my tank goes on for miles...... Should be an interesting trial and error build.....