Why isn't my coraline algae growing!

[Cubeman]

Just wondering how long this tank has been set up? I had a 90 gallon once that had all of the coralline on the newly introduced live rock turn white within the first few weeks of being set up. The tank looked sterile for 4 months and then by the 6 month mark it had 'purpled' up. Patience is often the key in this hobby.