The beneficial bacteria grows in the filter bed but the living organisms that come on the live rock or sand are different. Live rock contains certain algae and plantlife. Have you done a search on this BB. Someone else has asked a similar question and many have responded. I've just started with LR and not too familiar with it but do know that there is a difference and I'm learning all this as well.
Angel
Be very careful what kind of PLAY SAND you use.I have heard of only one that works in an aquarium,That is HomeDepo's southdown sand. As for dead coral,YES it will become LIVE with time. I have a large chunk in my tank that is every bit as "live" as my rock. Of corse the coral itself will not come back to life,but it will harbor all the stuff your live rock does with time.STEVE
Mr. Salty,
So you are saying that i can go to home depot and get southdown sand for my tank? I am sure it will be much cheaper than pet store sand...... let me know..... thank you
David C. Phan, D.C.