120 g tank start up advice please

[Junmity]

I just bought this 120g tank.

I want to set it up with a sump and use the existing plumbing.

The PO said that it was set up for a wavemaker and that is why there is a compartment on the end?

its 5" wide and 19" deep

the tank itself is 72" wide 19" deep and 19" high.

is there any point in keeping this compartment or can i remove it?

Any advice would be greatly appreciated.

Thanks!![ATTACH]Attachment 8936[/ATTACH]