Nuisance Algae

The Beginner Guide To Nuisance Algae

Updated 2024

Table of Contents

In the world of saltwater aquariums, nuisance algae refers to any type of rapid-growing algae or bacteria that can overtake your tank, prove challenging to eliminate, or pose harm to your aquatic life. These nuisances vary in appearance and impact, ranging from visually unappealing to potentially lethal for your tank inhabitants.

This guide provides a concise overview of the prevalent types of nuisance algae encountered by beginners, effective methods for eradicating them, and general strategies to prevent their proliferation in your aquarium.

I) What is Nuisance Algae

Nuisance algae are those that rapidly spread within a tank, blanketing rock structures and corals, making their removal a challenging task.

For instance, diatoms might fall under this category due to their unattractive appearance, but they often emerge during tank cycling and are relatively simple to eliminate.

Hair algae and bubble algae are prime illustrations of nuisance algae in marine aquariums. These varieties exhibit rapid growth, aren’t typically consumed by standard cleanup crews, and can swiftly dominate an entire aquatic environment.

Bubble Algae, © Bulk Reef Supply
Hair Algae, © Bulk Reef Supply

Defining nuisance algae isn’t set in stone, but if an algae is causing you trouble, it certainly qualifies as a nuisance!

These bothersome algae can be eradicated through manual removal, utilizing specific organisms, employing targeted chemical treatments, reducing phosphates, incorporating a refugium, and so on. The concept is clear!

Prevention is the ultimate solution for dealing with nuisance algae. Thoroughly quarantining your livestock aids in identifying problematic algae before they infiltrate your display tank.

1) Where Does Nuisance Algae Come From?

Nuisance algae can find their way into your aquarium through various avenues:

– Live Rock
– Fish
– Fish Food
– Corals
– Clean-Up Crew (CUC)
– Equipment
– Airborne

Just a single spore can trigger a nuisance algae takeover.

While fully eradicating nuisance algae is extremely challenging, you can adopt measures to minimize its likelihood. Thoroughly examining new livestock, implementing a quarantine tank, and practicing manual removal all contribute to this effort.

Being proactive and addressing issues as soon as they arise is your best approach.

1) What Causes Nuisance Algae to Grow?

There are two factors that cause nuisance algae growth:

a) Light

Similar to plants above the waterline, algae predominantly relies on photosynthesis for nourishment.

When devising the lighting schedule for your saltwater tank, consider that in natural habitats, most tropical fish experience approximately 10-12 hours of sunlight daily, with only 4-5 hours being characterized by intense photosynthetically active radiation (PAR) light. Thus, if your aquarium lights are on for 16 hours daily, anticipate increased algae growth.

Personally, I maintain a 12-hour lighting cycle, with a 4-5 hour window of intensified lighting.

Moreover, consider the impact of color spectrum on the proliferation of nuisance algae. When searching for “grow lights” on platforms like Amazon, you’ll often come across LEDs with a blend of red, purple, blue, orange, and white. Therefore, the key takeaway is to minimize the presence of red spectrum lighting in your lighting schedule.

b) Nutrient Levels

However, lighting isn’t the sole factor at play. Nuisance algae flourishes in environments abundant with nutrients, particularly high levels of phosphates and nitrates. Overfeeding and overcrowding your tank are two significant contributors to this scenario.

Employing a test kit regularly can aid in assessing nutrient concentrations. While reducing the amount and frequency of feeding is beneficial, the type of food you use also matters. For instance, pellet foods are densely packed with nutrients, and if uneaten or left to settle at the tank’s bottom, they can decompose into phosphates, leading to elevated nitrates.

In contrast, frozen food is generally less nutrient-dense and, especially when rinsed beforehand, can provide sustenance to your livestock without fueling algae growth.

Additionally, you can opt for an overly powerful protein skimmer and even contemplate incorporating a macroalgae refugium to counteract elevated nutrient levels.

II) How to Get Rid of Nuisance Algae

Dealing with nuisance algae for the first time can indeed feel overwhelming. The sight of it spreading across your live rock and potentially affecting your corals can be disheartening. While it’s crucial to address an outbreak promptly, there are 8 fundamental husbandry considerations that can significantly enhance your chances of long-term success.

1) Lighting

Less is indeed better when it comes to tackling algae issues. Nuisance algae tend to thrive under red/purple lights, so minimizing this spectrum can be beneficial.

The duration of your light cycle also makes a significant difference. There’s a notable contrast between a 12-hour day and a 16-hour day in terms of light exposure.

Moreover, the intensity of your lighting matters greatly. A stark contrast exists between running lights at 50% intensity versus 100% intensity.

To combat nuisance algae, consider these steps: reduce the red spectrum, shorten your lighting cycle, and lower the intensity. Try implementing a lighting schedule of 10 hours each day, including a four-hour period of higher intensity lighting, a two-hour ramp up/down, and a touch of moonlight at sunrise and sunset. This approach can significantly diminish algae growth—I assure you!

2) Clean Up Crew (CUC)

We’ve dedicated an entire Beginner Guide to Clean Up Crews, so I encourage you to give it a look!

Each member of a clean up crew has their strengths in tidying up, but no single member can handle every task. Plus, there are certain types of algae that seem to go untouched by anyone in the crew!

For instance, while some sources claim that hermit crabs and certain fish will devour hair algae, I’ve rarely witnessed this in practice.

Furthermore, be cautious of certain clean up crew members that could harm your corals or other fish.

So, as a newcomer to this complex realm, what’s the best approach? Here’s my suggestion.

Begin with snails. Opt for varieties that consume algae (Turbo, Trochus, Astrea) and those that tackle detritus (Cerith, Nassarius). From there, you can gradually diversify your crew. Starting with snails will give you a solid foundation!

However, don’t fall into the trap of believing that the ideal clean up crew will completely resolve your algae issues. It won’t, and you’ll still need to manually address nuisance algae now and then.

3) Manual Removal

Though manual removal can be quite the chore, it often serves as both your primary strategy and your shield. If you’re quick to spot nuisance algae in its early stages, you might find it localized to a single snail shell or a specific section of live rock. With careful handling, you can pluck it away, and presto, the potential outbreak is nipped in the bud.

I’ve personally experienced the effectiveness of manual removal, particularly in dealing with cyanobacteria (which isn’t algae but resembles it) and bubble algae. However, there’s a key trick to successful removal.

Simply reaching into the tank and trying to pull off the troublesome algae could inadvertently spread it around, allowing it to establish itself elsewhere. The best-case scenario involves removing the affected piece of live rock or livestock and dealing with the algae in a separate container.

If that isn’t feasible, the next best option is enlisting the help of a friend. Have your friend position a gravel vacuum directly above the algae while you work on removing it. As you dislodge the algae, the vacuum will suck up most of it, preventing its return to the tank.

4) Refugiums

If your available space and budget allow for it, incorporating a refugium can offer a natural way to lower your nitrates and phosphates.

Here’s the concept: Algae flourishes in environments where ample light and abundant nutrients are present in the water. When nutrient levels decrease, algae growth either slows down or diminishes (though that might sound a bit wishful!).

In a refugium, you introduce macroalgae (larger algae), provide lighting, and this beneficial algae begins to consume the phosphates and nitrates along with your unwanted algae. Over time, the macroalgae gains the upper hand over nuisance algae, consuming more nutrients and thus reducing the available resources for those more troublesome forms of algae.

Whether you have a sump in place or opt for a hang-on-back (HOB) refugium, this addition can significantly aid in addressing high nutrient levels.

5) Skimmers

Having a protein skimmer is not an absolute necessity for maintaining a successful reef tank. In my own setup, I have a 24-gallon saltwater aquarium containing several corals and a couple of fish, and I rely solely on live rock and a sponge for filtration.

However, it’s important to note that systems with elevated nutrient levels (due to either excessive fish population or overfeeding) can greatly benefit from the inclusion of a skimmer. A protein skimmer effectively eliminates those very fine particles that manage to pass through your filter socks.

If you find that your nitrates are registering high, it might be worth considering the addition of a protein skimmer. When selecting a skimmer, I would recommend opting to get one that’s just the right size, but error on the side of too small.  Going bigger is absolutely not better when it comes to protein skimmers

6) RO/DI Water

Experienced hobbyists are well aware that tap water isn’t suitable for creating saltwater. It can contain chlorine, chloramines, heavy metals, phosphates, and various other elements that are undesirable for your tank’s health.

If you’re grappling with nuisance algae issues and currently using tap water or well water, I strongly recommend transitioning to either RO/DI water or distilled water as your water source. This switch will contribute significantly to maintaining a more balanced and algae-resistant environment in your aquarium.

RO/DI Filter

7) Chemicals

While it’s certainly not my preferred approach, I must acknowledge that at times I’ve resorted to utilizing chemical solutions to combat nuisance algae in aquariums.

However, it’s crucial to understand the limitations and potential risks associated with this approach. There are only a handful of options available for addressing specific types of algae, and even among those, caution is warranted.

For instance, I’ve employed ChemiClean on several occasions with positive outcomes. ChemiClean serves as an antibiotic treatment for cyanobacteria, which resembles algae in appearance. Yet, it’s important to exercise care, as ChemiClean can deplete oxygen levels in the tank and adversely affect your aquatic life if not used judiciously.

Additionally, I’ve occasionally employed hydrogen peroxide for algae control, albeit sparingly within the aquarium itself, due to its potential to harm coral polyps even in small quantities.

I’ve heard favorable reports about Flux Rx for tackling bryopsis and hair algae, though I haven’t personally utilized it in my own setups.

8) Media & Reactors

Let’s start by discussing media options. You don’t necessarily need to invest in a dedicated reactor; instead, you can employ fine mesh bags to hold the media and position them in areas of strong water flow within your tank. Here’s a list of recommended media that I suggest for beginners seeking to address elevated nutrient levels:

  1. GFO (Granular Ferric Oxide) – Effective for phosphate removal.
  2. Activated Carbon – Useful for eliminating heavy metals, improving water color, and addressing odors.
  3. Chemi-Pure – Similar to carbon but enhanced with Purigen for nitrate removal.
  4. Purigen – Serves to reduce nitrate levels.
  5. Poly-Filter – Capable of removing ammonia, heavy metals, and phosphates.
  6. Ceramic Media Plates – Ideal for long-term ammonia and nitrate reduction.
  7. Ceramic Media Balls – Similarly effective for sustained ammonia and nitrate reduction.
  8. Biopellets – Offers prolonged ammonia and nitrate reduction benefits.

Most of these media options can be conveniently contained in a straightforward mesh bag, like the one depicted below. This approach provides a simple yet effective means of introducing these media into your system.

Except for ceramic and Poly-Filter options, using a reactor enhances the effectiveness of these media types. Why, you might wonder?

A reactor features an integrated pump that draws in aquarium water, directs it through the media within, and subsequently reintroduces the purified water into the tank. This constitutes active filtration, a more efficient approach compared to the passive method of using a filter bag.

Allow me to introduce my preferred combination of reactor and pump:

III) Most Common Types of Nuisance Algae

I want to emphasize once again that this guide is tailored for beginners! While there are more comprehensive resources available, my goal was to provide a simple and easily understandable overview of the most common types of nuisance algae. This way, beginners can immediately benefit without having to spend hours searching the internet!

If you don’t find information about your specific type of nuisance algae here, simply enter “saltwater nuisance algae guide” into Google, and you’ll discover additional valuable information.

1) Diatoms

  • Description: Diatoms are practically a guarantee in new aquariums. They tend to appear during the nitrogen cycle and can persist for several months afterward. These brown, unsightly microorganisms might cover your glass, substrate, and live rock, but there’s no need for concern.

    Methods of Removal: The easiest way is manual removal. Gently scrape them off glass or acrylic surfaces. For the sandbed, a gravel vacuum can help, and you can use a brush to delicately clean live rock. However, diatoms usually disappear on their own, so cleaning the sandbed and live rock might not be necessary.

    Best Cleanup Crew (CUC) Options: Opt for algae-eating snails like Turbo, Trochus, Astrea, and Nerites to maintain clean glass. Ceriths, Nassarius Snails, and Conches are great choices to keep the sandbed well-maintained.

2) Film Algae

Film Algae, © Marine Depot
  • Description: This algae is typically green and forms a layer on your aquarium glass, obstructing your view of the inhabitants inside. It’s likely the most prevalent type of algae in saltwater tanks, and while you can’t prevent it entirely, there are ways to manage it. Personally, I clean film algae off my glass tanks every 3-4 days. There are two types: soft film algae, which can be removed with a felt pad, and hard film algae that requires a stainless steel blade or box cutter blade for removal.

    Methods of Removal: Manual removal is the most effective approach. I highly recommend the Flipper magnetic algae scraper. It features a soft felt side for the easy-to-remove film algae and a stainless steel (or plastic for acrylic tanks) side for the more stubborn encrusting algae.

    Best Cleanup Crew (CUC) Options: Employing algae-eating snails can significantly reduce the need for manual removal. Turbo snails, Trochus, Astrea, and Nerite snails are excellent choices for maintaining the algae situation in check.


3) Hair Algae

  • Description: Green Hair Algae (GHA), as it’s commonly known, doesn’t have a precise definition since hobbyists use this term for a variety of algae species. However, as shown in the picture, this algae forms clumps resembling long hair strands. Despite the varied species, it’s characterized by its hair-like appearance and tendency to clump together. This pesky algae can rapidly take over your tank, covering corals and live rock.

    Methods of Removal: Immediate action is crucial when spotting any green hair algae. If you can, remove the affected live rock piece. Otherwise, use a gravel vacuum and your hands to eliminate as much as possible. Diminish your lighting duration and intensity if feasible, and employ the techniques mentioned in section II to lower nutrient levels. Timely intervention is vital to prevent it from spreading throughout your tank.

    Best Cleanup Crew (CUC) Options: GHA can be challenging to control with CUC members alone. While Hermit Crabs and Emerald Crabs are often suggested, I’ve found manual removal to be the most effective solution, as other methods tend to yield limited results.

Python 2" Gravel Vacuum on a white background

4) Bubble Algae

Bubble Algae, © Marine Depot
  • Description: Bubble Algae earns its name due to its distinct appearance – small bubbles tightly clustered together. This type of algae can proliferate swiftly, underscoring the importance of proactive prevention.

    Methods of Removal: Prevention serves as the primary defense against Bubble Algae. Thoroughly inspect any new additions such as snails, live rock, or stony corals, and promptly remove any instances of bubble algae. If it does infiltrate your tank, exercise caution when attempting removal. Simply scraping it off can detach the bubbles, which will then float around and find new spots in your tank. For effective elimination, consider removing the affected live rock from your tank before attempting removal. Alternatively, use a gravel vacuum or turkey baster to minimize the risk of spreading this persistent algae.

    Best Cleanup Crew (CUC) Options: Opt for emerald crabs to assist with Bubble Algae removal. However, be cautious, as certain emerald crabs have been observed nipping at and feeding on corals.

5) Turf Algae

© My First Fish Tank
  • Description: Turf algae is a catch-all term used by enthusiasts to describe a diverse range of algae species. This classification generally encompasses densely clumped algae that either forms robust mats that can be peeled off or sprouts directly from the rock. The provided image showcases the concentrated clusters of turf algae, with some hair algae visible near the bottom.

    Methods of Removal: Eradicating turf algae can prove challenging, particularly when dealing with the variety that seems to emerge directly from the rock. If it’s feasible to do so, remove the affected rock, perform thorough manual removal, and apply hydrogen peroxide to the impacted areas. In instances where removing the rock isn’t an option, diligently keep up with manual removal to manage the algae growth.

    Best Cleanup Crew (CUC) Options: While I’ve experienced limited success with other methods, some recommendations commonly emerge, including the use of Emerald Crabs and Sea Urchins.

5) Cyanobacteria (not algae)

  • Description: Commonly referred to as blue/green algae or Red Slime Algae, this bacterium presents a formidable challenge for removal. While it often manifests as a deep red hue in my tanks, it can also exhibit shades of green or blue. While not inherently harmful to your aquatic inhabitants, its appearance is certainly unappealing. Elevated lighting, excessive nutrients, and inadequate water flow all contribute to its proliferation.

    Methods of Removal: I’d advise resorting to ChemiClean only as a final recourse. Begin by enhancing the flow within your tank to eliminate stagnant areas. Adjust your lighting regimen, reducing both its duration and intensity. Employ a vacuum to manually extract as much of the algae as possible and utilize a bristle brush for scrubbing the live rock. Concentrate on lowering your phosphates, either through water changes or the use of a suitable phosphate-removing medium like GFO. Should all other efforts prove ineffective, consider ChemiClean. However, exercise caution and adhere closely to the provided instructions, as improper use could lead to oxygen depletion and the potential loss of livestock.

    Best Cleanup Crew (CUC) Options: Regrettably, there aren’t many effective solutions when it comes to this bacterium. It appears that none of the usual clean-up crew members are willing to consume it.

7) Bryopsis

By Hervey, A. B. -, Public Domain,
  • Description: Unfortunately, I couldn’t find an appropriate copyright-free image to include here, but this will suffice! While I haven’t personally encountered bryopsis in my tank, it possesses a distinctive structure, reminiscent of a miniature pine tree or fern.

    Methods of Removal: You have a couple of options for addressing bryopsis. Manual removal is one approach, or you can consider using a product like Flux RX. This particular algae is notorious among hobbyists due to its formidable resilience. If feasible, it’s advisable to remove the affected live rock from the tank before attempting to eradicate the algae. In case other methods prove ineffective, Flux RX is an option, though it’s crucial to meticulously adhere to the provided instructions. Alternatively, you might attempt to starve the bryopsis by decreasing phosphates, nitrates, and light exposure, but this requires a patient approach over time.

    Best Cleanup Crew (CUC) Options: This is a tricky one! Bryopsis is a persistent nuisance in part because standard clean-up crew members have limited impact on it. While there isn’t a definitive solution, you could give Emerald Crabs a shot, although success might be uncertain.

8) Dinoflagellates

dinoflagellate algae clumped together on a white sandbed. Light brown in color with air bubbles attached to the end
Dinoflagellates, © Bulk Reef Supply
  • Description: Picture the appearance of gravity-defying brown gelatin with a buoyant air bubble suspended at its tip. Identifying Dinoflagellates, or Dinos, becomes evident when your snails or crabs exhibit unexplained fatalities. These organisms are toxic to invertebrates, and their presence is met with trepidation in the hobby.

    Methods of Removal: Eradicating Dinos can be a formidable task, and I’ve faced my own challenges with them over the years. Incorporating a UV sterilizer can offer some assistance. Unlike other types of algae, Dinos are believed to thrive in low-nutrient environments where nitrate and phosphate levels plummet to zero. The initial step involves elevating your phosphate and nitrate levels above zero. Next, reintroduce beneficial bacteria to your tank; I recommend either Dr. Tim’s or Brightwell MicroBacter 7. Consistently manually remove as much Dinos as possible each day. Be aware that this is a gradual process requiring persistence. It might span several weeks before results are noticeable.

    Best Cleanup Crew (CUC) Options: Unfortunately, there aren’t any viable options. Dinos pose a danger to invertebrates due to their toxicity, rendering traditional clean-up crew members ineffective.

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