Can I make a suggestion? Pull away the background photo, and give the back pane of glass a really good clean, perhaps using a dusting cloth that has been sprayed with window cleaner (don't spray at the tank or you'll poison the fish!). Let the back pane dry thoroughly, preferably overnight. Then put the background photo back on.
You'll find the circular bubble-like markings on the glass will vanish, and the overall look of the tank will improve dramatically.
For what it's worth, it's best to choose rocks for decorating your tank that match the background photo. That way, the illusion is more realistic. As it is, your rocks, though nice in their way, are totally different to the rocks on the photo. If your background has a plain black side, consider turning the backdrop around and seeing how that looks; with very colourful fish like mbuna, the effect of a plain black background can be rather good.
Cheers, Neale