Encrusting Coralline Algae is what gives many saltwater aquariums their color and a good covering is the goal of most marine aquarists. Coralline Algae exists in a variety of different colors (green, pink, white, purple, red).
Unlike Brown, Green Hair and Red Slime Algae, which (frequently) grow in your tank whether you like it or not, Coralline Algae must be physically brought into your tank in order for it to reproduce and populate the various surfaces. Coralline Algae can be introduced to your tank by installing:
Coralline covered Live Rock
Coralline scrapings from another tank
Commercial Coralline Algae starter packages
The more types of Coralline (green, pink, white, purple, red) that you add to your tank, the more you will see growing on your Live Rock, substrate and aquarium walls.
Once you have some Coralline Algae in your tank, how do you get it to reproduce and spread throughout your tank? One simple method is to turn off all tank filters and skimmers, leaving any powerheads running. With a single edged razor blade, scrape the existing Coralline off the front and side tank walls. The water current generated by the powerhead will spread the Coralline scrapings throughout the tank where they will continue to grow. After an hour or so, turn the skimmers and filters back on.