Just got my first clam. A blue/green crocea. I have a 75 gal. (48*18*21 depth)tank with 4'' sand bed .for lighting I have 4*54watt tek t5 fixture. My question is will my crocea be ok on the sand bed on a small rock? or should it be moved up? lighting is 2 blue+, 1 aqua , 1 daylight.