I feel like I need more rock, personally. I dont want the cinder block to be exposed, it wont be. Im going to put cement and salt mixture over the cinder block, to make it look more lik a rock, than cinder block. Im just going to be using the cinder block as a base, since it already has caves made. I'll have some rocks in front of the cinder blocks anyhow, they'll be burried behind the two rock stacks that I currently have. They'll mainly be used to lift up this shelf that I want.
Then, Im going to make some more, to support that rock lift on the right hand side. Rather than a couple rocks, which might shift and what not.
I like the canyon type look that I have going, but I think the tank would be complete with a shelf type overhang coming out a good 12-14" from the back of the tank, and maybe a little rock wall on top of the shelf, going to the very top of the tank.