rock replacement

The new clean rock will attract bugs and worms over time. Bacteria populations can double in as little as half an hour when there is food available. Life starts to move into clean new rock immediately and as algae begins to grow on the rock and as particles of detritus/uneaten food settle on it, more and more life makes it home.

The algae in the pic of Vida Rock does resemble green Coralline but without a closeup shot it's hard to say. Be sure to have plenty of snails to keep the tops of the rock from growing hair algae. It starts as a fuzz but can get out of hand much too quickly.
Side note- that powerhead appears to be pointing diagonally down. It will do a better job if it points diagonally up.

no problem.