For Fluval Roma 240 tank you will need a made to measure 3d background. Your tank has a crossbar so the background has to be cut into 2 parts. Secondly in your tank's right bottom corner, there are filter pipes, which can cause problems when installing a 3d background. Our 3d backgrounds have a very irregular shape and they may not fit between the glass the filter pipes.
You would need to extend the original filter pipes with a flexible hose and then run the hose through the 3d background to have a good circulation. The background can't cover both filter pipes as it will limit the water circulation. That's why you need to play a bit with the filtration pipe. The suction inlet should be located close to the bottom in front of the background and the outlet pipe has to be at the top corner in front of the background.
For your tank, you will need a 117x45cm background cut into 2 parts. The background has to fit under the brace bar.
Please goooogle :
Aqua Maniac Fluval Roma 240
and you will find what you need :)
Thanks
Chris