Since your sand is already in place....don't forget to support your rock so it doesn't fall if you add tunneling livestock. If you put the rock on the sand something will inevetibly tunnel under it causing a crash.
it would become liverock if you leave it in there for long period of time.
how many hours a day did you let your lights on ?? i think at this stage,2-4 hours a day is the best,since anyway you dont have any livestock in there.
