Approx.

Crustose Coralline Algae (CCA)

Scientific name: Multiple families (Corallinaceae): Porolithon, Hydrolithon, Lithothamnion Taxonomic type: Calcified rhodophyte Water: For marine use only Color: Pink, purple, red, orange, lilac, white Texture: Hard as cement, encrusting, calcareous

⭐ This algae is DESIRABLE—it's a sign of a healthy reef.

Appearance: A hard, pink-purple coating that covers the rocks, the rear and side glass, and the equipment. Rocks covered with CCA are the most highly valued (“premium live rock”). It is not flat—it has a raised surface and a rough texture.

Why is it good?:

• Indicates proper water chemistry (Ca, KH, Mg within range)
• Provides a substrate for coral larvae to settle on
• It competes with unwanted algae by taking up space
• Very attractive design
• Indicates system stability

Requirements for growth:

• Approx. 400–450 ppm
• KH: 8–12 dKH
• Mg: 1,250–1,350 ppm
• pH: 8.1–8.3
• Light: Moderate to high (does not require as much as SPS corals)

Should I delete it?:

• About the front windshield: Yes, with a scraper (it leaves marks on the glass)
• Rear and side glass: Many aquarists let it grow
• On rocks and decoration: never—it's beneficial

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