Nuisance Algae in the Reef Aquarium – Part III

Nuisance Algae in the Reef Aquarium – Part III
By: Scott Zachow

Nuisance Algae in the Reef Aquarium – Part III
By: Scott Zachow

Well here we are, 5 months after the first article was published in this series on removing nuisance algae from my own reef aquarium. The task has not been easy, and I wasn’t expecting it to be. What I wanted to accomplish in this series was to provide hope. Many newcomers to the marine aquarium hobby have, and will continue to face challenges with undesirable algae such as those I encountered. Many of these same newcomers won’t stick around long, fearing that the money and efforts they spent were wasted only to have a tank full of unsightly algae they cannot control or get rid of. Who can blame them? Besides, having a tank full of green algae that smothers everything in its growth path isn’t what inspired them to get salt on their hands. The inspiration was more likely a beautiful display of marine fish at their areas finest restaurant. Or perhaps they visited a local fish store whose caretaker had a display of colorful Acropora spp. with long branches and small Chromis viridis swimming through them. Maybe it was the common inspiration that comes when the symbiotic relationship between an Anemone fish and its host was observed. Whatever it was, I will say with certainty that it wasn’t a reef exhibit that was plagued with Derbesia sp. algae and bright white coral skeletons that once lived on the reef structure before the polyps were smothered and eventually killed. As they say, beauty is in the eye of the beholder. I have to believe however, that a tank full of green filamentous alga isn’t what the caregiver is after when setting up an expensive marine system.

The marine aquarium hobby is much different today than it was 10 years ago. With advancements in technology and better understandings of captive requirements, a saltwater aquarium isn’t out of the reach of anyone with a little bit of a disposable income and some dedication. That doesn’t mean that problems won’t pop-up, or are non-existent. Unexplained deaths in fish and corals, disease, and of course, the dreaded nuisance algae outbreaks are all things that hobbyist still experience today. The difference is that today we have a better understanding of how to prevent these problems, or at least reduce the probability of their occurrence. Even still these problems can rear their ugly heads and we must be ready to fight them. Rest assured there are plenty of ways to fight off the troubles of marine aquariums, including nuisance algae. There are also plenty of ways to add to the problem like using “miracle cures” and “magic elixirs” marketed to cure your tank of problems and end poverty in the modern world all with one dose. I assure you that the only way to fix a marine aquarium problem is through diagnosis and hard work. And poverty, well we’ll leave that to the politicians.

This picture recently taken of the right side of the aquarium shows the elimination of all of the nuisance algae except a little bit of Valonia sp..

The Good, The Bad, And The Ugly

There are over 7,000 species of green algae; most of them are aquatic. Yet only a few of them are commonly recommended in the marine aquarium. How often have you heard someone recommend buying a couple of rocks covered in hair algae to place in their refugium? Both Caulerpa spp. and Derbesia spp. are green algae from the phylum Chlorophyta, which use chlorophyll A to capture light energy to produce carbohydrates. They both also utilize phosphates and nitrates in their growth. But why don’t people recommend hair algae? The answer might be in the appearance. Although not recommended, aquarists could easily place rocks with hair algae into their refugiums, prune it often and have the same type of nutrient control as they would with Caulerpa spp. The same could be said for Bryopsis and Chaetomorpha. Yet Bryopsis and Derbesia are not used for these purposes, at least not on purpose. All of these algae exist in nature and for the same reasons, nutrient consumption. And when they appear in a captive marine aquarium it is because the conditions are right for their growth. When someone says they are having a problem with nuisance algae, they are effectively having a problem with nutrient control. Adding Caulerpa spp. to a separate vessel is often recommended as a cure since they too utilize the same components for their survival. But you have to hope that the algae purposely added will out-compete the less desirable algae.

A picture of our green Montipora sp. that has been in teh aquarium since the red algae outbreak described below.

In the reef aquarium, there are many different ways to remove nutrients from the system, including adding other algae that will uptake the same nutrients at a faster rate (because they grow faster). This always isn’t practical and alone, not even guaranteed. If nuisance algae are present in the aquarium, they may still consume the available nutrients quicker than the more desirable algae that were added to a refugium. This will lead to the desired algae dieing off due to a lack of available nutrients and the nuisance continuing to flourish. As a different approach, you might try to take some of the nuisance from the display and add it to the separate vessel. The hope here is that the amount in the separate vessel will grow faster and out compete what remains in the display. My point here is if the appearance of the algae consuming the nutrients isn’t an issue, use the same algae that is already flourishing, except in a different, out of sight, vessel. Caulerpa spp., Chaetomorpha or Derbesia spp.; it doesn’t matter as all would consume the same nutrients in the same manner.

Having a separate vessel to grow algae for nutrient consumption isn’t always feasible; it wasn’t in my case. When it’s not, the aquarist must look at other ways to remove the nutrients from the system. Protein Skimming and water changes are effective methods and should be used even in nutrient poor systems or those containing refugiums for algae growth. Without this separate vessel, more aggressive skimming and water changes might be necessary. Even with the more aggressive water corrections, manual removal should be done. For our algae infestations, we were able to get rid of the turf algae and hair algae through water exchanges, but not the Bryopsis. This alga required a lot of tedious manual removal in addition to the heavy skimmer production and water changes. The difficult part with removing algae like Bryopsis is that the thallus easily breaks and floats away. It is difficult to get a good grasp of a bunch and remove it without it breaking away. This loose thallus will float and get hung up elsewhere in the aquarium and quickly grow into a new bush. The edges of porous liverock are a great place for it to get hung up on. Once the thallus is caught, if not removed before it begins to grow and gains a foothold, you have a new bushel in no time that will need to be removed. Because of this, when you are manually removing algae you should quickly remove any broken pieces that are floating in the aquarium. To do this, we used a fish net and scooped it from the water column. Siphoning it out is another method that could be used however you would have to be quick to catch it all.

A nice frag of Montipora sp. that is growing in a plating form with white polyps.

Monster Rings and Cages