My 300 gallon Drop Off Reef Tank Build

[Gripenfelter]

I went a different way for the sump. Instead of one big tank I decided to go with 3 smaller ones. It allows me to isolate a certain chamber if there is an issue or if I want to change something later.



Got my RO system up and running. Filling sump as we speak.

QUESTION:

A local aquarium builder told me it would be better to fill in the section under the drop off completely with sand, worms, and crabs and make a deep sand bed as opposed to filling it with some rocks and running a pump in there to circulate water.

Opinions?

In other words fill in this section with deep sand (imagine a piece of glass across the top):