Week 4: Growing Macroalgae in a Refugium – The Power of Plants in Your Tank

One of the main reasons people add a refugium to their aquarium is to grow macroalgae. These algae not only absorb excess nutrients but also provide a safe and natural habitat for beneficial organisms. Here’s everything you need to know about growing macroalgae in your refugium.

Why Grow Macroalgae?

Macroalgae play a crucial role in nutrient control within your aquarium. They absorb nitrates, phosphates, and other excess nutrients that can lead to harmful algae blooms in your main tank. By growing macroalgae in your refugium, you’re helping to maintain water quality and reduce the likelihood of undesirable algae taking over your display tank.

Types of Macroalgae for Refugiums

Here are four types of macroalgae you should consider for your refugium:

1. Chaetomorpha (Chaeto): This is the most common type of macroalgae used in refugiums. It’s fast-growing, easy to maintain, and very effective at removing excess nutrients. Plus, it doesn’t go sexual easily, making it a great choice for beginners. Chaeto grows in tangled mats, which are perfect for trapping debris and creating hiding spaces for small creatures like copepods.
2. Sea Lettuce (Ulva): Sea Lettuce is a green, leafy macroalgae that thrives in nutrient-rich water, absorbing both nitrates and phosphates. It grows quickly and is ideal for nutrient export in a refugium. Regular harvesting is key to preventing it from overgrowing and taking over your refugium. Sea Lettuce also provides excellent grazing material for herbivores in your aquarium.
3. Red Ogo (Gracilaria): Red Ogo is a red macroalgae that’s known for its attractive color and excellent nutrient-exporting capabilities. It’s effective at absorbing excess phosphates and nitrates and is often used as a food source for herbivores. Red Ogo adds both beauty and functionality to your refugium.
4. Pom Pom (Cladophora): Pom Pom is a bright red with burgundy hue macroalgae that forms clumps resembling pom-poms. It’s great for absorbing nutrients and provides a hiding place for small critters in the refugium. While not as common as other algae, it’s an excellent addition for variety and nutrient export.

Setting Up for Macroalgae Growth

To grow healthy macroalgae in your refugium, you’ll need:

1. Proper Lighting: Macroalgae need light to thrive, so make sure your refugium is lit with a full-spectrum light. Aim for a 12-hour light cycle to mimic natural daylight. Ensure the light is not too close to prevent overheating or algae burn.
2. Water Flow: Moderate water flow is ideal for macroalgae growth. Too much water movement can cause the algae to break apart, while too little can hinder its growth. Ensure the water is gently circulating.
3. Nutrient Balance: Macroalgae will only grow well if there’s an adequate amount of nutrients (nitrates and phosphates). Ensure your water conditions are optimal for their growth and consider testing water parameters regularly.

Harvesting and Maintenance

Regularly harvesting your macroalgae is essential to prevent it from overgrowing and taking over your refugium. Remove small portions of algae every few weeks to keep it from becoming too dense, and ensure it continues to grow healthily.

Troubleshooting Macroalgae Problems

• Algae Die-Off: If your macroalgae is dying off, check your lighting, water flow, and nutrient levels. A lack of nutrients or improper lighting is usually the culprit.
• Excessive Growth: If your algae is growing too fast, consider harvesting more frequently or adjusting your lighting.

Conclusion of the Series

Refugiums are a fantastic tool for improving the overall health of your aquarium. From providing natural filtration and water quality improvements to creating a safe haven for beneficial organisms, they offer a wide range of benefits for both beginners and experienced aquarists alike. Whether you’re growing macroalgae or creating a sanctuary for small critters, a refugium will help maintain the balance in your tank and make your aquarium thrive.