Coralline Algae

Visual Diagnostics (Desirable & Troublesome)

• Morphology: Exhibits as hard, flat crusts or nodular formations spreading radially across bare substrate, glass, and equipment.
• Pigmentation: Dominated by deep pinks, vivid purples, and deep reds, driven by the presence of phycobiliproteins (phycoerythrin and phycocyanin).
• Equipment Interference: Unchecked growth heavily encrusts powerhead impellers, wavemaker rotors, and heating elements, drastically reducing mechanical efficiency and leading to premature hardware failure.
• Acrylic Degradation: On acrylic aquariums, removal of deeply embedded CCA can result in permanent microscopic scratches.

Growth Vectors

• Alkalinity and Calcium: Hyper-proliferation occurs only in environments strictly adhering to optimal reef chemistry: Alkalinity between 8-11 dKH, Calcium between 400-450 ppm, and Magnesium maintained >1300 ppm.
• Seeding Dynamics: Introduction via 'seed' rock or purposeful manual scraping of existing crusts, which releases microscopic viable spores into the water column.
• Illumination Spectra: CCA strongly favor moderate PAR environments biased toward actinic blue spectra; excessive high-intensity lighting often results in photoinhibition and cellular bleaching of the algae.

Eradication from Hardware

• Acid Dissolution: The only reliable mechanism to remove CCA from hardware is chemical dissolution of the $CaCO_3$ matrix. Submerging pumps and heaters in a heated bath of Citric Acid (1 cup per gallon) or diluted Acetic Acid (white vinegar) for 12-24 hours safely dissolves the aragonite structure.
• Mechanical Scraping: Regular maintenance of viewing panels using specialized stainless steel razor blades (for glass) or high-density plastic cards (for acrylic).

Growth Management

• Urchin Grazing: Introduction of highly effective biological controls, particularly the Tuxedo Urchin (Mespilia globulus), which possess exceptionally strong Aristotles Lantern mouthparts capable of masticating the calcareous crusts.
• Asterina Predation: Certain species within the Asterina starfish complex naturally prey exclusively upon coralline algae, keeping populations restricted.
• Routine Husbandry: Instituting strict bi-weekly acid-baths for all rotating mechanical equipment to prevent calcium carbonate buildup from causing irreversible rotor friction damage.