Algae-the green, the brown, the slimy, and sometimes the downright ugly. Every aquarist, whether you're a newbie or a seasoned pro, has encountered algae at some point in their tank’s life cycle. While algae is a completely natural part of the aquatic ecosystem, when it spirals out of control, it can lead to unsightly blooms and threaten the health of your reef tank. So, how can you tackle the different types of algae that invade your space? Let’s dive in and get your tank looking pristine again.
Diatoms: The Brown Plague
You’ve just set up your new reef tank, and BAM—brown powdery slime everywhere. This is diatoms at work, a common nuisance algae that loves to settle on your rock and sand. Diatoms thrive in new tanks, often appearing during the initial cycling phase.
How to Beat Diatoms:
- Patience is Key: In new tanks, diatoms usually clear up on their own after a few weeks. Keep up with regular maintenance and water changes to prevent a full-blown outbreak.
- UV Sterilizers: These can help prevent diatoms from spreading by targeting the microalgae in the water column.
- Natural Grazers: Add some brackish fish, like sailfin mollies or black mollies, to help graze on the diatoms.
- Phosphate Removal: Use GFO (Granular Ferric Oxide) to reduce phosphates and silicates, cutting off the food source for the diatoms.
Cyanobacteria (Red Slime Algae): The "Not-Quite-Algae"
It may look like algae, but cyanobacteria (or "red slime") is actually a photosynthetic bacteria that thrives in fluctuating water conditions. It’s an opportunistic bacteria that can grow in low-nutrient environments, often taking hold in the quieter, low-flow areas of your tank.
How to Beat Cyanobacteria:
- Increase Circulation: Use extra wave pumps to improve water flow and eliminate dead spots where cyanobacteria love to thrive.
- Vacuum the Substrate: Regularly vacuum your substrate and remove the cyano manually with a siphon tube.
- Fix Nutrient Imbalances: If you have low or zero nutrients, it can be just as bad as excess nutrients. Maintain balanced levels of nitrates and phosphates.
- Chemical Treatments: If all else fails, you can use a chemical treatment, but be sure to follow the instructions carefully.
Green Hair Algae: The Tangled Mess
This is the stuff of nightmares for many reefers. Green hair algae (GHA) loves bright light and high phosphate levels, often growing into thick, tangled mats that smother your rocks and outcompete corals. Left unchecked, it can become nearly impossible to remove.
How to Beat Green Hair Algae:
- Manual Removal: Remove hair algae as soon as you spot it. It’s easier to tackle in the early stages before it gets too out of hand.
- Grazers to the Rescue: Introduce herbivorous invertebrates like snails, urchins, and even sea hares, or add algae-eating fish like tangs, rabbitfish, and algae blennies to keep GHA under control.
- Phosphate Control: Excess phosphates fuel hair algae growth. Use phosphate-removing media or an algae scrubber to reduce nutrient levels.
- Scrub Rocks: If it gets really bad, remove the rocks and scrub them clean, although this may not completely solve the problem.
Bubble Algae: The Sneaky Invader
Bubble algae (Valonia) is a sneaky pest that attaches itself to rocks, often going unnoticed until it’s already starting to spread. Left unchecked, bubble algae can smother your rockwork and even block water flow, causing pump malfunctions.
How to Beat Bubble Algae:
- Manual Removal: Carefully remove bubble algae by hand. You can use forceps or aquascaping tools to avoid breaking the bubbles and releasing spores.
- Emerald Crabs: These little guys are natural bubble algae specialists and can help keep the outbreak under control. However, you may need multiple crabs for severe infestations.
- Chemical Solutions: Use products like Brightwell Razor to clean surfaces, making it harder for bubble algae to attach.
Macroalgae: When Seaweed Invades
Macroalgae is usually a welcome addition to a refugium, where it helps compete with nuisance algae by absorbing excess nutrients. However, when it escapes into the main display tank, it can outcompete your corals for space and light.
How to Beat Macroalgae:
- Grazers: Fish like rabbitfish, surgeonfish, and angelfish will help prevent macroalgae growth by grazing on it.
- Manual Removal: Large macroalgae can be removed easily by hand or with the help of urchins, which graze on it efficiently.
- Control Nutrients: Maintain proper nutrient levels in your tank to prevent an overgrowth of macroalgae.
Calcareous Algae: The Purple Menace
While some hobbyists love the vibrant pink and purple hues of coralline algae, too much of it can lead to problems. Calcareous algae, while a sign of good water parameters, can quickly compete with corals for calcium, magnesium, and alkalinity.
How to Beat Calcareous Algae:
- Scrape It Off: If it's growing on glass, use an algae magnet or razor blade to scrape it off. Just be careful not to scratch the glass.
- Urchins: These spiky critters will graze on coralline algae, helping to control its spread.
- Equipment Cleaning: Regularly clean pumps and equipment with citric acid or a vinegar-water solution to remove buildup.
Dinoflagellates: The Brown Plague 2.0
Dinoflagellates are often mistaken for diatoms or cyanobacteria, but they’re actually marine plankton that produce stringy brown mats. These pests can wreak havoc, smothering sand and rocks, and producing unsightly slime.
How to Beat Dinoflagellates:
- Manual Removal: Siphon out the mats and perform regular water changes to keep their numbers in check.
- Nutrient Control: Maintain proper water parameters and nutrient levels. Imbalanced nitrates and phosphates can trigger a dinoflagellate outbreak.
- Blackout Periods: Since dinoflagellates are photosynthetic, blacking out the tank for a few days has been shown to help starve them.
- Beneficial Bacteria: Add bacteria supplements to help outcompete dinoflagellates for resources.
Conclusion: Keeping Your Tank in Check
Algae and pests are an inevitable part of the aquarium hobby, but they don’t have to ruin your reef tank. By staying on top of your tank’s water parameters, maintaining good circulation, and introducing natural grazers, you can keep algae outbreaks in check and your corals happy.
FAQs
Q1: How do I prevent algae from growing in my reef tank?
A1: To prevent algae, maintain stable water conditions, control nutrient levels, increase water circulation, and introduce algae-eating fish and invertebrates like snails and urchins.
Q2: Can I remove algae manually, or do I need chemicals?
A2: Yes, manual removal is often effective, especially for algae like hair algae and bubble algae. Chemical treatments can be used when manual methods fail, but they should be used carefully.
Q3: Is it normal for diatoms to appear in a new tank?
A3: Yes, diatoms are common in new tanks and usually clear up after a few weeks. Just make sure to keep up with water changes and regular tank maintenance.
Q4: How can I get rid of red slime (cyanobacteria)?
A4: Increase water circulation, vacuum your substrate, and correct any nutrient imbalances. Manual removal and chemical treatments can also help control cyanobacteria.
Q5: Will adding an algae scrubber help with nuisance algae?
A5: Yes, algae scrubbers can help by removing excess nutrients from the water and providing a competitive environment for algae, reducing the chances of a bloom.
