largest grain size substrate?

[njp14333]

what's the largest grain size substrate? (besides florida crushed coral)

 

[Julio]

coral rubble that is atually a little larger than pebbles.

 

[njp14333]

i was thinking more along the lines of like a large grain sand/shell mix. any ideas?

 

[Julio]

that will work just find as long as you are not putting in conch shells.