Center overflows can be good and bad. It all comes down to how you scape it. If you get some branch rock you can do so really cool things comming off the overflow.
You could attach branch rock from the top of the overflow, all at an angle comming off each side of it and create a "floating branch jungle. Not one rock touching the bottom of the tank. Fill the branches with acros. That would looks so dope. Then fill the bottom of the tank with chalices and incrusting monti's
Yea it is quite nice.
Darkening or painting the back would draw your eye to the center. I'm kinda guessing you won't be painting anytime soon.
But there is a product called coroplast it's a black carboard. Easy enough to to neatly tape and dress. It's plastic so won't saturate with water or salt.
Yeah... this is what I was originally planning with my old cube until I started realizing how much space it would take up.
Instead, we did the corner overflow with dry docks for the vortechs.
Still let us walk around the tank with only a small portion that wasn't viewable.
Was able to fit Herbie plumbing and a dry pipe for wiring, but ended up wishing the dry pipe was quite a bit bigger.
Other than that it was a great setup.