If I might make a suggestion? On rock arrangement, years ago rock walls,eg piled up against the back glass were very popular ,like this picture, then we found that often muck piled up behind in some cases and caused problems. So we went for islands or call um towers.
This allowed circulation all round .
I had a system with a “reef clean” which had egg crate on some glass ridges which extended from the rear for a third of the way foreward ,it then had a pipe like a spray bar connected to the closed loop system which you turned on from time to time to flush out rubbish .
Anyhow heres a few differing pictures .