You could make a shelf on the back corner. Keep in mind the light runs 24/7 so I’d probably recommend carbon dosing. The other option is go Sean mode, have a few beers and stare at the tank thinking I bet I could drill that hahahahaha
You can make an internal scrubber that runs off of air bubbles. I think it's called an upflow scrubber. Look up joey the king of diy on YouTube , he shows you how to do it.