Check your ca level and assure light intensity is somewhat elevated.
running light at least 12hrs a day Will promote coraline but algae also. As with other forms of algae, coralline algae requires light. Exactly how much or little light is required for optimum growth varies with the types of coralline algae. Some prefer higher lighting, while others prefer low lighting.
High Mag can impact coraline growth.
Unlike brown, GhA and red slime algae, all of which frequently grow in an aquarium whether you like it or not, coralline algae must be physically brought into the aquarium for it to reproduce and populate the various surfaces.
Coralline algae can be introduced into your aquarium by adding:
-Coralline-covered live rock
- Coralline scrapings from another aquarium
- Coraline starter packages
The more species of coralline algae that you add to your aquarium, the more you will see growing on your live rock, substrate and aquarium walls. An advantage of growing coralline algae is that it out-competes the growth of nuisance algae like hair algae, green algae, diatoms, and mat algae (in a normal reef environment with proper water chemistry). Coralline algae grows on live rock where nuisance algae might otherwise grow.
- Be sure to add cleaner crew to prevent other algae’s from growing too aggressively