How much CoraroC you need is a matter of taste and what you prefer. CoraroC is optimized to make a minimalistic or "negative" aqua scape with a lot of room for fish and corals. Of course, it is very easy to just add more CoraroC along the way.

It is also possible to combine CoraroC with live rock or dry rock. If you have a tank running, you can just add a branch or shelfing part of CoraroC to the existing scape.