If I put in live sand, would that effectively do the same thing? Right now I have a lot of dead coral rock in my tank, and I would have to take a lot of it out. I was thinking if I bought some live sand, I could place it on top of the existing sand in my tank, and it wouldn't have too much of an impact on space. Does this seem to be a good idea?

Does the live sand spread to the dead coral rock and existing sand to make it live as well?

If so, how much live sand would I need?