John, thanks for the reply. That information is very useful.

One other question I have is that I read somewhere that you shouldn't
put rock on top of live sand(???) They said that it would kill the
sand and create toxic matter. Is this true? If I'm using live sand
from the start in my tank, how would I possibly avoid putting rocks
(live rock in this case) on top of the sand?!

Regareds,

- MB