“Area 51” Reef

By Immo Gerber
Excerpt from CORAL Magazine
July/August 2020

Yes, my aquarium has a name: Area 51.

It is included in the title of this article for a specific reason. A good verbal portrait usually begins, “Let me introduce myself, my name is …” I am following that convention here. As I am sometimes asked what the connection is between my reef tank and the legendary, conspiracy-theory-shrouded, US Air Force top-secret air base in Nevada, I will explain myself. But I must go into some background first.

Have a look at this reef on the author’s YouTube Channel. It is in German, but the viewer can turn on closed captions (CC) and have then auto-translated into English.

The initial idea

After I re-entered the marine aquarium hobby and operated a 37-gallon (140-L) Cubicus aquarium from AquaMedic for about three years, I had the opportunity to move up to a larger tank. I planned to use this opportunity to realize an idea: with the cooperation of the companies Fauna Marin (Germany) and Cairns Marine (Australia), I would select the population of my new aquarium so that all the livestock—i.e. corals, fishes, and invertebrates—along with the rock, would be taken from only a relatively limited area of reef and more or less from the same depth. I was interested in discovering whether differences could be detected from conventional reef-aquarium communities, which are often put together arbitrarily with a broad range of species, mostly on the basis of color, but which don’t come close to representing an authentic biotope.

Above all, I wanted to see whether such a tank would develop differently, as the main difference from the natural coral reef and the area of reef in question would be limited to the artificial environment in a closed system, and would no longer involve the communal housing of creatures that would never encounter each other in the wild. The latter case is the norm; the average reefkeeper often doesn’t have the first idea where his or her corals or fishes came from. Unfortunately, for various mainly logistical reasons, this project couldn’t be realized with Cairns Marine.

The second idea

While browsing the Internet three years ago, I came across photographs of a coral called “Walt Disney.” It was probably an Acropora tenuis, and it was so spectacularly colored that I, like many others, couldn’t escape the impression that it must have been touched up considerably using Photoshop or other means, and that nothing of the sort could exist in reality. At that time, this spectacular coral color morph had only turned up in the United States, which made the whole thing even more interesting to me.

I was so fascinated by this coral that I began to dig deeper. I found out that these color morphs were available in the trade in Germany, and after I learned what to look out for when making a selection, I managed to acquire some of these coveted corals.

And so the theme for my new tank, not a purist’s biotope at all, was found: namely, differing fluorescent effects in certain SPS corals. These specimens differ from other members of their species in that they exhibit an enormous variety of colors and color differentiation, especially under predominantly blue lighting with the aid of filters (photography) or tinted glasses (visual)—but often under the usual 14,000-Kelvin lighting, albeit usually not as intensely.

I searched carefully and found various Acropora tenuis color morphs to be the most suitable, but A. millepora, A. prostrata, a few others also fit the bill. The desired effects were most apparent in specimens from Indonesia. Plus, Indonesia, and Bali in particular, were way ahead at that time (compared to Australia or the Fiji Islands) in terms of the frequency of importations. There was a good chance that there would be at least one specimen with the desired properties in any incoming shipment of corals.

These mysterious, brilliant corals differed so much from those with ordinary color pigmentation that I thought of them like something from another world. And that’s how the new aquarium came to receive the name “Area 51,” after the top-secret USAF base where spy aircraft have been developed and, reportedly, alien space vehicles are brought for study and reverse engineering. Located on Groom Lake, Area 51 is also reputed to be used by the Air Force to study extraterrestrial life forms. I find the name extremely appropriate, as when I look into my dark aquarium in the evening and see all the corals fluorescing enigmatically in all the colors of the rainbow, I can imagine I am dealing with life forms from another world. And, in a way, that is the case: the sea isn’t our habitat—its underwater world isn’t ours.

A new style in the reef aquarium hobby

It was at that time that Fauna Marin developed its US Style Primefrag System, which is intended to bring out the most vivid colors possible in naturally fluorescing corals. The company says its proprietary supplements “consist of the well-known, tried and true elements, but also include trace and micronutrients, marine proteins, biopolymers, and enzymes.” Fauna Marin prescribes the use of LED lighting with strong blue, cyan, royal blue, and UV channels, in a Berlin-system setup with excellent skimming, ozone dosing, and regular ICP water analysis.

Initially, this new type of coral maintenance was used primarily for presentation (e.g. for photography under blue-dominated lighting using yellow or orange filters); it was quite exotic at the outset, and many people laughed at it. It polarized reefkeepers in Europe: those who placed the fluorescent colors of the corals to the forefront were branded as color fetishists. Initially, many of those who saw my aquarium photos were as skeptical about the colors of the corals as I had been.

Nowadays, about three years after the first publications in Europe, corals with this strong fluorescent effect are so widespread here that they are no longer unusual. Views on the color-loving approach to the hobby are still divided, and not everyone can identify with it, but many regard this concentration on colorful corals with the emphasis on fluorescent effects as an enrichment of the hobby—especially because these corals have been widely available for years. The focus was previously on the bright colors of corals, but without reference to their fluorescent effects.

Marine aquariums in North America are traditionally illuminated with a preponderance of blue light, and this may have led to the deliberate selection of coral color morphs whose genetic disposition permits particularly strong fluorescence. Some coral farms have even specialized in color morphs of this type, especially in Bali, and they fetch very high prices for them.

Constructing the reef

Now we can come back to my tank, beginning with the reef construction. It was clear to me from the start that I didn’t want a mixed tank; I wanted one that was dominated by SPS corals. I decided against bottom substrate because of my conviction that this makes nutrient concentrations easier to control, and because I didn’t want the current strength to be limited by the problem of suspended particles of substrate. You can, of course, select a larger grain size to rule out the latter problem, but in my view that has disadvantages for maintenance and doesn’t jive with my preferred aesthetics.

Apropos of aesthetics: many reef aquarists, wanting a more “natural” look, are against doing without bottom substrate. I, on the other hand, find a bottom covered with live corals a lot more attractive than one covered with sand. The maintenance effort is also appreciably less than with substrate, and there are few (if any) limitations on current. In addition, the coral-covered bottom has an important side effect: it doesn’t offer an unnecessarily large area for nuisance organisms (e.g. cyanobacteria) to colonize. By contrast, poorly maintained coral sand rapidly allows problems to arise. A no-substrate approach does, however, require a bit of patience until the entire bottom glass is reasonably densely covered.

I created the reef structure from a combination of dry rock for the foundation and live reef rock for the upper part, in a ratio of roughly 1:1 in an island or mound formation. I wouldn’t design the reef structure itself again in that way now, as it has weaknesses in the lateral view. Some of the table corals are by now quite large, protruding and shading these areas so that it is virtually impossible for corals to establish there. I am not pleased with the large, dark spaces that dominate the lower third of the reefscape.

The lighting

I have several special light-measuring devices, because this subject is close to my heart. I had to come to grips with the nature of LED lighting, because initially the light spectra generated had less than optimal physiological effects. This has now changed, although there is certainly still room for optimization.

By taking measurements from a wide variety of lighting systems, I was able to obtain a good overview, and I used it to choose my tank lighting. The aquarium is illuminated by four Radion XR30w G4 PRO units. The daily photoperiod is 12 hours, and the lighting profile, which came from EcoTech pre-installed, is called “Shallow Reef Template.” I chose to imitate a water depth of about 45 feet (13 m) and a cloud probability of 30 percent.

I set the maximum intensity to 65 percent. I find the simulated passing of clouds to be a valuable feature, as it somewhat reduces light stress on the corals. When using it, there is no prevailing constant, homogeneous light intensity—it mimics the was light fluctuates in the wild.

The cloud cover is simulated in such a way that the probability of a cloudy day can be set as a percentage (0–100 percent) using a slider. The program dims the lighting accordingly over a random period of time and thus simulates a cloudy sky. You can also enter the probability of a storm in much the same way as the cloud cover. (I chose 20 percent for that.) During the simulation, the current pumps (from the same manufacturer) are run counter to their actual control program for some time, with higher output. This endeavors to simulate a full day of bad weather. I am very satisfied with both the VorTech current pumps and the Radion XR30w G4 PRO.

I compare the growth rate and color of freshly acquired coral fragments via photographic documentation. The interval between individual photos is around three months.

The supply system

I initially used the Fauna Marin Balling Light system to supply the tank with calcium, magnesium, alkalinity and trace elements. I eventually adopted the Fauna Marin’s US Style Primefrag System of reef aquarium husbandry in the course of time. Because in the beginning there was little or no information on how this type of coral husbandry to maximize color effects could be managed and maximized, I experimented by offering various foods and testing various light settings.

Over time I discovered that the corals don’t necessarily have to be kept under blue-biased lighting in order to develop these fluorescent effects. These were also present to some extent under 14,000º Kelvin lighting, but under white daylight the corals were simply just brown. In addition, some corals didn’t seem to grow as well, but this was due more to increased nutrient concentrations.

To begin, I had deliberately kept these higher, as I had assumed that the corals were more dependent on planktonic food, given the lower light intensity in the greater depths of the sea, which I believed to be their provenance. Because there isn’t much live plankton in my aquarium, I concluded that it might be beneficial to tend towards higher nutrient concentrations, although this turned out to be incorrect. In fact, these corals exhibit the most vivid colors and vigorous growth when maintained with the usual low-nutrient concentrations.

Blue-biased lighting is helpful for viewing the fluorescent effects, because these effects are more pronounced than at lower Kelvin values (e.g. 14,000º K). But if you want to perceive these fluorescent effects strongly, it is advisable to use yellow- or orange-tinted sunglasses, as this helps our eyes with something that might be termed white balance (our color receptors are optimized for daylight color). The result is that you perceive an almost breathtaking color differentiation; you see the corals in a different light—in both senses of the phrase. The same applies to photography: yellow or orange filters help with the white balance of camera sensors optimized for daylight, so you are better able to display the actual color rendition.

Ups and downs

Naturally, there were not only positive developments in my aquarium, but also negative ones. Let us consider the latter first.

The phosphate problem About two years after start-up, a phosphate problem developed. The use of appropriate adsorbers rose to undreamed-of heights. I suspected the reason for this was the initial higher-than-usual nutrient concentrations, and maybe also the dry reef rock I used. I looked at alternatives to conventional phosphate adsorbers, but my problems seemed to defy a solution. In addition, it was becoming very expensive.

I found the solution eventually: I used lanthanum chloride (LC), which binds with phosphate and forms a white residue that can be easily removed by filtration. I used 90 ml of Elmiphos from Tropic Marin, which I added to 2 liters of reverse-osmosis water and administered directly into the reactor chamber of the skimmer with wand thus achieve the desired value in a manner well tolerated by corals. (I also did not want to dose the LC directly into the display tank, where it might impact fishes and other livestock.) Lanthanum also has the advantage of reacting with the phosphate (lanthanum phosphate), which permits the removal of existing deposits and can even prevent them from forming. Using the method described above, I was able to keep my PO₄ value at exactly the desired concentration over a period of 18 months without losses. It is the cheapest method of phosphate control for a reef aquarium that I know of, and the most precise with regard to dosing.

It was clear to me that I was only curing symptoms, but I didn’t find the cause of the high nutrient concentration at first. The lanthanum helped me keep the tank stable and to avoid the serious negative impacts of high phosphate levels.

One day I had the idea of siphoning out my overflow chamber. I now realize that this is a construction flaw in my setup. The chamber box has the drainpipe and emergency overflow positioned at the top in the interest of noise reduction, just below the desired water level in the tank. As a result, there is no active water flow through the lower part of the chamber itself. During this check, I came across the remains of five or six large Turbo snails. When I siphoned it, out a viscous black soup appeared, accompanied by an extremely strong smell of sulfur. Eureka! I had finally found a stagnant pocket of pollution hidden deep in the filter system of my tank. I am now “lanthanum-free.” Just a small algae filter from SkimZ now keeps my phosphate concentration at around 0.03 mg/L.

Bryopsis thread algae The tank had a problem with this thread algae right from the start, but it was limited to the overflow gate and chamber during the first 18 months. Bryopsis has a major tendency to block the outflow slots, making the water level in the main tank gradually rise; because of the falling water level in the sump, the automatic top-up “thinks” that water has evaporated, and it adds freshwater refills. Regular cleaning of the outflow combs was a must.

As was to be expected, the algae gradually spread into the tank. Eventually I decided to treat the aquarium with fluconazole, an anti-fungal medication that requires a prescription, although over-the-counter aquarium-use capsules are available in the US. It should be used responsibly, including when disposing of leftover medication or aquarium water containing chemicals.

The treatment is quite simple in practice: add a single dose of about 5–10 mg of fluconazole per liter of aquarium water to the tank after first dissolving it in a few liters of aquarium water. Activated carbon, skimmer, zeolite, etc. shouldn’t be used for six days thereafter. In order to avoid doing without oxygenation by the skimmer, it will suffice to unscrew the foam cup so that no flotate is collected. Now you can almost watch the Bryopsis population slowly but surely deteriorating and dying. When the six days are up, everything can be put back into operation as usual. I couldn’t detect any negative side effects.

Fluconazole inhibits the development of fungi by inhibiting the enzyme activity of certain proteins, causing defects in the cell membranes to develop due to disrupted metabolic processes. I don’t know how the effect on algae comes about, though. I have heard that it has been used successfully by some aquarists to fight Valonia bubble algae, but I can’t confirm this from my own experience.

Acropora-eating Flatworm I am currently battling against this very unpleasant plague, which is usually shorthanded as AEFW. It has so far proven effective to blow-clean all the corals thoroughly with a Reefbuster from Fauna Marin, or similar products from other manufacturers (baster-like devices). This results in many of the flatworms being shredded in the current pumps, and it disrupts their reproduction.

The Six-Line Wrasse (Pseudocheilinus hexataenia) and the Scribbled Pipefish (Corythoichthys intestinalis) are said to perform good service in controlling these hitchhikers. But from my own bitter experience, I must advise against using pipefishes in reef aquariums with a strong current, especially if the propellers of the pumps are not protected by fine mesh or foam. Sooner or later, the pipefishes will be sucked in, and their fate is usually sealed.

Using a pair of Six-Line Wrasses and the above-mentioned water jet-cleaning of infected corals, I have so far been able to successfully curb the flatworms and keep them under control. Corals that were previously badly affected have already recovered almost completely.

Positive developments

Despite the difficulties described, I have succeeded in keeping the growth and color development of the corals in this aquarium at a high level for more than three years. I am also learning a huge amount about the color development of the corals, which motivates me to overcome difficulties and continue further along on this path.

Because I have a spectrometer as well as a quantum meter and a PAM chlorophyll fluorescence measuring device available, I can experiment a little in the matter of the light spectrum, especially in the context of photosynthesis, and this gives me a lot of pleasure. As far as I know, there aren’t many scientific research results on the subject directly related to marine aquariums.

In “Area 51”, the positives predominate, even negative developments can be readily surmounted, especially if you treat them as an integral part of the hobby and regard them more as a challenge. You may follow me on YouTube, where I report on everything relating to this aquarium in my discussion section (see QR code at the end of the article). I hope this small glimpse of my “Area 51” has sparked your interest in the new and alien world of reefkeeping.

ONLINE:
YouTube Videos: AREA 51 “Aquariumplausch mit Immo”

By Immo Gerber
Excerpt from CORAL Magazine
July/August 2020

Yes, my aquarium has a name: Area 51.

It is included in the title of this article for a specific reason. A good verbal portrait usually begins, “Let me introduce myself, my name is …” I am following that convention here. As I am sometimes asked what the connection is between my reef tank and the legendary, conspiracy-theory-shrouded, US Air Force top-secret air base in Nevada, I will explain myself. But I must go into some background first.

Have a look at this reef on the author’s YouTube Channel. It is in German, but the viewer can turn on closed captions (CC) and have then auto-translated into English.

The initial idea

After I re-entered the marine aquarium hobby and operated a 37-gallon (140-L) Cubicus aquarium from AquaMedic for about three years, I had the opportunity to move up to a larger tank. I planned to use this opportunity to realize an idea: with the cooperation of the companies Fauna Marin (Germany) and Cairns Marine (Australia), I would select the population of my new aquarium so that all the livestock—i.e. corals, fishes, and invertebrates—along with the rock, would be taken from only a relatively limited area of reef and more or less from the same depth. I was interested in discovering whether differences could be detected from conventional reef-aquarium communities, which are often put together arbitrarily with a broad range of species, mostly on the basis of color, but which don’t come close to representing an authentic biotope.

Above all, I wanted to see whether such a tank would develop differently, as the main difference from the natural coral reef and the area of reef in question would be limited to the artificial environment in a closed system, and would no longer involve the communal housing of creatures that would never encounter each other in the wild. The latter case is the norm; the average reefkeeper often doesn’t have the first idea where his or her corals or fishes came from. Unfortunately, for various mainly logistical reasons, this project couldn’t be realized with Cairns Marine.

The second idea

While browsing the Internet three years ago, I came across photographs of a coral called “Walt Disney.” It was probably an Acropora tenuis, and it was so spectacularly colored that I, like many others, couldn’t escape the impression that it must have been touched up considerably using Photoshop or other means, and that nothing of the sort could exist in reality. At that time, this spectacular coral color morph had only turned up in the United States, which made the whole thing even more interesting to me.

I was so fascinated by this coral that I began to dig deeper. I found out that these color morphs were available in the trade in Germany, and after I learned what to look out for when making a selection, I managed to acquire some of these coveted corals.

And so the theme for my new tank, not a purist’s biotope at all, was found: namely, differing fluorescent effects in certain SPS corals. These specimens differ from other members of their species in that they exhibit an enormous variety of colors and color differentiation, especially under predominantly blue lighting with the aid of filters (photography) or tinted glasses (visual)—but often under the usual 14,000-Kelvin lighting, albeit usually not as intensely.

I searched carefully and found various Acropora tenuis color morphs to be the most suitable, but A. millepora, A. prostrata, a few others also fit the bill. The desired effects were most apparent in specimens from Indonesia. Plus, Indonesia, and Bali in particular, were way ahead at that time (compared to Australia or the Fiji Islands) in terms of the frequency of importations. There was a good chance that there would be at least one specimen with the desired properties in any incoming shipment of corals.

These mysterious, brilliant corals differed so much from those with ordinary color pigmentation that I thought of them like something from another world. And that’s how the new aquarium came to receive the name “Area 51,” after the top-secret USAF base where spy aircraft have been developed and, reportedly, alien space vehicles are brought for study and reverse engineering. Located on Groom Lake, Area 51 is also reputed to be used by the Air Force to study extraterrestrial life forms. I find the name extremely appropriate, as when I look into my dark aquarium in the evening and see all the corals fluorescing enigmatically in all the colors of the rainbow, I can imagine I am dealing with life forms from another world. And, in a way, that is the case: the sea isn’t our habitat—its underwater world isn’t ours.

A new style in the reef aquarium hobby

It was at that time that Fauna Marin developed its US Style Primefrag System, which is intended to bring out the most vivid colors possible in naturally fluorescing corals. The company says its proprietary supplements “consist of the well-known, tried and true elements, but also include trace and micronutrients, marine proteins, biopolymers, and enzymes.” Fauna Marin prescribes the use of LED lighting with strong blue, cyan, royal blue, and UV channels, in a Berlin-system setup with excellent skimming, ozone dosing, and regular ICP water analysis.

Initially, this new type of coral maintenance was used primarily for presentation (e.g. for photography under blue-dominated lighting using yellow or orange filters); it was quite exotic at the outset, and many people laughed at it. It polarized reefkeepers in Europe: those who placed the fluorescent colors of the corals to the forefront were branded as color fetishists. Initially, many of those who saw my aquarium photos were as skeptical about the colors of the corals as I had been.

Nowadays, about three years after the first publications in Europe, corals with this strong fluorescent effect are so widespread here that they are no longer unusual. Views on the color-loving approach to the hobby are still divided, and not everyone can identify with it, but many regard this concentration on colorful corals with the emphasis on fluorescent effects as an enrichment of the hobby—especially because these corals have been widely available for years. The focus was previously on the bright colors of corals, but without reference to their fluorescent effects.

Marine aquariums in North America are traditionally illuminated with a preponderance of blue light, and this may have led to the deliberate selection of coral color morphs whose genetic disposition permits particularly strong fluorescence. Some coral farms have even specialized in color morphs of this type, especially in Bali, and they fetch very high prices for them.

Constructing the reef

Now we can come back to my tank, beginning with the reef construction. It was clear to me from the start that I didn’t want a mixed tank; I wanted one that was dominated by SPS corals. I decided against bottom substrate because of my conviction that this makes nutrient concentrations easier to control, and because I didn’t want the current strength to be limited by the problem of suspended particles of substrate. You can, of course, select a larger grain size to rule out the latter problem, but in my view that has disadvantages for maintenance and doesn’t jive with my preferred aesthetics.

Apropos of aesthetics: many reef aquarists, wanting a more “natural” look, are against doing without bottom substrate. I, on the other hand, find a bottom covered with live corals a lot more attractive than one covered with sand. The maintenance effort is also appreciably less than with substrate, and there are few (if any) limitations on current. In addition, the coral-covered bottom has an important side effect: it doesn’t offer an unnecessarily large area for nuisance organisms (e.g. cyanobacteria) to colonize. By contrast, poorly maintained coral sand rapidly allows problems to arise. A no-substrate approach does, however, require a bit of patience until the entire bottom glass is reasonably densely covered.

I created the reef structure from a combination of dry rock for the foundation and live reef rock for the upper part, in a ratio of roughly 1:1 in an island or mound formation. I wouldn’t design the reef structure itself again in that way now, as it has weaknesses in the lateral view. Some of the table corals are by now quite large, protruding and shading these areas so that it is virtually impossible for corals to establish there. I am not pleased with the large, dark spaces that dominate the lower third of the reefscape.

The lighting

I have several special light-measuring devices, because this subject is close to my heart. I had to come to grips with the nature of LED lighting, because initially the light spectra generated had less than optimal physiological effects. This has now changed, although there is certainly still room for optimization.

By taking measurements from a wide variety of lighting systems, I was able to obtain a good overview, and I used it to choose my tank lighting. The aquarium is illuminated by four Radion XR30w G4 PRO units. The daily photoperiod is 12 hours, and the lighting profile, which came from EcoTech pre-installed, is called “Shallow Reef Template.” I chose to imitate a water depth of about 45 feet (13 m) and a cloud probability of 30 percent.

I set the maximum intensity to 65 percent. I find the simulated passing of clouds to be a valuable feature, as it somewhat reduces light stress on the corals. When using it, there is no prevailing constant, homogeneous light intensity—it mimics the was light fluctuates in the wild.

The cloud cover is simulated in such a way that the probability of a cloudy day can be set as a percentage (0–100 percent) using a slider. The program dims the lighting accordingly over a random period of time and thus simulates a cloudy sky. You can also enter the probability of a storm in much the same way as the cloud cover. (I chose 20 percent for that.) During the simulation, the current pumps (from the same manufacturer) are run counter to their actual control program for some time, with higher output. This endeavors to simulate a full day of bad weather. I am very satisfied with both the VorTech current pumps and the Radion XR30w G4 PRO.

I compare the growth rate and color of freshly acquired coral fragments via photographic documentation. The interval between individual photos is around three months.

The supply system

I initially used the Fauna Marin Balling Light system to supply the tank with calcium, magnesium, alkalinity and trace elements. I eventually adopted the Fauna Marin’s US Style Primefrag System of reef aquarium husbandry in the course of time. Because in the beginning there was little or no information on how this type of coral husbandry to maximize color effects could be managed and maximized, I experimented by offering various foods and testing various light settings.

Over time I discovered that the corals don’t necessarily have to be kept under blue-biased lighting in order to develop these fluorescent effects. These were also present to some extent under 14,000º Kelvin lighting, but under white daylight the corals were simply just brown. In addition, some corals didn’t seem to grow as well, but this was due more to increased nutrient concentrations.

To begin, I had deliberately kept these higher, as I had assumed that the corals were more dependent on planktonic food, given the lower light intensity in the greater depths of the sea, which I believed to be their provenance. Because there isn’t much live plankton in my aquarium, I concluded that it might be beneficial to tend towards higher nutrient concentrations, although this turned out to be incorrect. In fact, these corals exhibit the most vivid colors and vigorous growth when maintained with the usual low-nutrient concentrations.

Blue-biased lighting is helpful for viewing the fluorescent effects, because these effects are more pronounced than at lower Kelvin values (e.g. 14,000º K). But if you want to perceive these fluorescent effects strongly, it is advisable to use yellow- or orange-tinted sunglasses, as this helps our eyes with something that might be termed white balance (our color receptors are optimized for daylight color). The result is that you perceive an almost breathtaking color differentiation; you see the corals in a different light—in both senses of the phrase. The same applies to photography: yellow or orange filters help with the white balance of camera sensors optimized for daylight, so you are better able to display the actual color rendition.

Ups and downs

Naturally, there were not only positive developments in my aquarium, but also negative ones. Let us consider the latter first.

The phosphate problem About two years after start-up, a phosphate problem developed. The use of appropriate adsorbers rose to undreamed-of heights. I suspected the reason for this was the initial higher-than-usual nutrient concentrations, and maybe also the dry reef rock I used. I looked at alternatives to conventional phosphate adsorbers, but my problems seemed to defy a solution. In addition, it was becoming very expensive.

I found the solution eventually: I used lanthanum chloride (LC), which binds with phosphate and forms a white residue that can be easily removed by filtration. I used 90 ml of Elmiphos from Tropic Marin, which I added to 2 liters of reverse-osmosis water and administered directly into the reactor chamber of the skimmer with wand thus achieve the desired value in a manner well tolerated by corals. (I also did not want to dose the LC directly into the display tank, where it might impact fishes and other livestock.) Lanthanum also has the advantage of reacting with the phosphate (lanthanum phosphate), which permits the removal of existing deposits and can even prevent them from forming. Using the method described above, I was able to keep my PO₄ value at exactly the desired concentration over a period of 18 months without losses. It is the cheapest method of phosphate control for a reef aquarium that I know of, and the most precise with regard to dosing.

It was clear to me that I was only curing symptoms, but I didn’t find the cause of the high nutrient concentration at first. The lanthanum helped me keep the tank stable and to avoid the serious negative impacts of high phosphate levels.

One day I had the idea of siphoning out my overflow chamber. I now realize that this is a construction flaw in my setup. The chamber box has the drainpipe and emergency overflow positioned at the top in the interest of noise reduction, just below the desired water level in the tank. As a result, there is no active water flow through the lower part of the chamber itself. During this check, I came across the remains of five or six large Turbo snails. When I siphoned it, out a viscous black soup appeared, accompanied by an extremely strong smell of sulfur. Eureka! I had finally found a stagnant pocket of pollution hidden deep in the filter system of my tank. I am now “lanthanum-free.” Just a small algae filter from SkimZ now keeps my phosphate concentration at around 0.03 mg/L.

Bryopsis thread algae The tank had a problem with this thread algae right from the start, but it was limited to the overflow gate and chamber during the first 18 months. Bryopsis has a major tendency to block the outflow slots, making the water level in the main tank gradually rise; because of the falling water level in the sump, the automatic top-up “thinks” that water has evaporated, and it adds freshwater refills. Regular cleaning of the outflow combs was a must.

As was to be expected, the algae gradually spread into the tank. Eventually I decided to treat the aquarium with fluconazole, an anti-fungal medication that requires a prescription, although over-the-counter aquarium-use capsules are available in the US. It should be used responsibly, including when disposing of leftover medication or aquarium water containing chemicals.

The treatment is quite simple in practice: add a single dose of about 5–10 mg of fluconazole per liter of aquarium water to the tank after first dissolving it in a few liters of aquarium water. Activated carbon, skimmer, zeolite, etc. shouldn’t be used for six days thereafter. In order to avoid doing without oxygenation by the skimmer, it will suffice to unscrew the foam cup so that no flotate is collected. Now you can almost watch the Bryopsis population slowly but surely deteriorating and dying. When the six days are up, everything can be put back into operation as usual. I couldn’t detect any negative side effects.

Fluconazole inhibits the development of fungi by inhibiting the enzyme activity of certain proteins, causing defects in the cell membranes to develop due to disrupted metabolic processes. I don’t know how the effect on algae comes about, though. I have heard that it has been used successfully by some aquarists to fight Valonia bubble algae, but I can’t confirm this from my own experience.

Acropora-eating Flatworm I am currently battling against this very unpleasant plague, which is usually shorthanded as AEFW. It has so far proven effective to blow-clean all the corals thoroughly with a Reefbuster from Fauna Marin, or similar products from other manufacturers (baster-like devices). This results in many of the flatworms being shredded in the current pumps, and it disrupts their reproduction.

The Six-Line Wrasse (Pseudocheilinus hexataenia) and the Scribbled Pipefish (Corythoichthys intestinalis) are said to perform good service in controlling these hitchhikers. But from my own bitter experience, I must advise against using pipefishes in reef aquariums with a strong current, especially if the propellers of the pumps are not protected by fine mesh or foam. Sooner or later, the pipefishes will be sucked in, and their fate is usually sealed.

Using a pair of Six-Line Wrasses and the above-mentioned water jet-cleaning of infected corals, I have so far been able to successfully curb the flatworms and keep them under control. Corals that were previously badly affected have already recovered almost completely.

Positive developments

Despite the difficulties described, I have succeeded in keeping the growth and color development of the corals in this aquarium at a high level for more than three years. I am also learning a huge amount about the color development of the corals, which motivates me to overcome difficulties and continue further along on this path.

Because I have a spectrometer as well as a quantum meter and a PAM chlorophyll fluorescence measuring device available, I can experiment a little in the matter of the light spectrum, especially in the context of photosynthesis, and this gives me a lot of pleasure. As far as I know, there aren’t many scientific research results on the subject directly related to marine aquariums.

In “Area 51”, the positives predominate, even negative developments can be readily surmounted, especially if you treat them as an integral part of the hobby and regard them more as a challenge. You may follow me on YouTube, where I report on everything relating to this aquarium in my discussion section (see QR code at the end of the article). I hope this small glimpse of my “Area 51” has sparked your interest in the new and alien world of reefkeeping.

ONLINE:
YouTube Videos: AREA 51 “Aquariumplausch mit Immo”

Area 51: https://en.wikipedia.org/wiki/Area_51

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