Of all the elements that make up our aquarium, light is perhaps the most important. The first thing we must take into account prior to illuminate the aquarium is the type of animals that will inhabit. Each biotope has certain characteristics of lighting that does not always coincide. Is not the same love to play a Mediterranean biotope, a piece of the Cantabrian coast or reef aquarium. However, all light is indispensable as a source of life by the food chain that supports this. Therefore we will be careful when choosing the type of lighting to install in our aquarium. Perhaps the most spectacular aquarium is the reef as it is one of the richest in terms of marine life is concerned, however, is also the most demanding in terms of lighting. The lighting in an aquarium is one element that should not cut corners.



When speaking of light, many factors come into play in order to understand the characteristics of each type of light. Also, these features produce a number of effects on the biology of living things. Therefore, it is necessary to clarify a priori all concepts that come into play in order to make a proper assessment. Therefore, we will try to make them known clearly. If someone asks what color the light, we would say that in any case is white. However, what most people know is that white is actually the sum of many colors. All colors visible light spectrum together give the white appearance. We all know the natural phenomenon of the rainbow. This phenomenon is not only the decomposition of light as it passes through the water, constituting the latter as a filter that breaks the white light in all its components. The same can be observed when using a disk stripes painted with all the primary colors we do rotate rapidly. The optical effect produced is that the colors disappear, leaving a white print.

When we see any color, really what we see is the sum of several joint printing and as a result gives us the color we see. However, human beings are not perceived in an objective light. We see a lot more green and yellow light than blue or red. Therefore, an aquarium illuminated with actinic light seems dark, when it really is not. However, it is desirable that the aquarium is well lit and we can see properly. The properties of light are its wavelength, energy and intensity.
The wavelength is a simple measure of distance between wave crests 2. Measure the distance between them using the metric system. The longer radio waves can be measured about 30.00 meters. The shorter the gamma ray measuring one hundred billionth of a meter. However, the unit used to mediate the wavelength is a nanometer (nm). The frequency is therefore the time that is emitted by a light wave in one space. Within a light as we saw earlier today a collection of various colors. Each of these colors have different wavelengths.
The power of light waves is electromagnetic in nature. This energy varies depending on the size of the wave but inversely to the apparent. That is, the shorter waves have more energy than long ones. Thus, for example red is rapidly absorbed light only penetrate the water. This example is particularly important in the design and choice of spectrum for the marine aquarium, as we shall see later.
Particular intensity is the emission of light by a source. Is expressed in lumens. This factor is one that becomes more important when judging the lighting in the aquarium. When purchasing a light, one of the factors to be analyzed will be a strength. Sometimes artificial lights come with 2 issues related to its intensity. The first number refers to the intensity of the new lamp. The second relates to the intensity and with hours of operation (half-life).

Lighting of Lamp TuboIluminación


Light travels in a vacuum at 300,000 miles per second. In the atmosphere, down a bit. However, when half the water 1000 times denser than air, the speed in the water column of light down to 200,000 km / s. This is because the light penetrates the water 2000 times worse than in air. The visible light we receive from the Sun ranges from red (700nm) to violet (400nm). However, in the marine waves shorter and longer are attenuated rapidly as the water is very opaque with respect to UV and especially red light, but quite transparent to light blue and green. This feature makes the oceans as they go deeper, are turning into monochrome. This feature mentioned is particularly important because in the coral reefs in the light that prevails in a majority is light blue. Below the first 10 to 15 feet deep, almost nothing is red and yellow, being the only reigning light green and mostly blue.

This finding is particularly important when keeping invertebrates in the aquarium, as we shall see. The visible radiant energy has two important functions in the marine environment. First, provide information to the environment allowing the animals to form images of what they see in their brains. Second, provide the plant kingdom of the energy needed to produce food with which generate their own organic matter. In all life processes, photosynthesis undoubtedly ranks first in the range of importance, since the self-generation of organic matter from the plant kingdom is the first link in the chain of life. Indeed, if there were no plant kingdom, there is nothing organic, and therefore would not exist as specialized predators.
In tropical and equatorial zones which is where all the coral reefs located, the typical seasonal variations in higher latitudes, or are not produced or are produced, but much softer. As it is in autumn or winter, the Sun’s altitude is lower on the vertical and the angle of incidence of light on the ocean surface is also smaller. This is leading to the phenomena of reflection, which carry a certain percentage decrease of light penetration into the water. Similarly, the degree of light penetration also varies according to the morning-afternoon. The maximum penetration is reached at 12.00 midday sun, just as the sun emits light perpendicular to the surface of the ocean. In tropical areas is usually measured when the sun is at its zenith around 150,000 lumens at the ocean surface. Of that amount, due to the phenomena of reflection and absorption, can penetrate only about 95,000 lumens in the water. But these lumens are decreasing rapidly, so that below the 150 feet deep darkness is almost there. The penetration of light in the ocean’s surface also depends on the weather now. If the day is calm, the reflection rate is only 4%. However, if not, will produce a rate of about 25%. Under these conditions, only 20% (about 15,000 lux) penetrates to about 15-20 meters deep. It is precisely at a depth of 10 meters, where it reaches the maximum rate of photosynthesis by native organisms (plants) and where you can measure about 30000-35000 lux.

The light saturation point is different for each type of alga. This phenomenon of saturation occurs when the light intensity reaches a point where the chloroplasts have reached the maximum photosynthetic activity. The compensation point is the light intensity where the production of oxygen from photosynthesis is sufficient to compensate for oxygen consumption during respiration of the plant or algae. Any algae that gets sunlight below the compensation point may die.

It is of fundamental importance to know that most marine invertebrates the type of coral, anemones, etc, contain within their outdoor fabrics, living within their own cells (endosymbiotic), a series of microscopic algae called zooxanthellae. These algae have a relationship of symbiosis with invertebrates in which they live. This relationship is that in exchange for the algae to live in a place protected from external aggressors, optimally arranged to capture sunlight with which to perform photosynthesis (invertebrate), synthesized by a series of photosynthesis of carbohydrates that yield in part to invertebrate and generating the amino acid used as food which builds tissue and organic substances.

These features of many marine invertebrates makes the main food source comes not capture plankton through its tentacles, but over 90% of its full power comes from these zooxanthellae that synthesize carbohydrates: its guests. From here, we’re taking the enormous importance of light as a giver of life to the reef. Somehow, we see how the reef acts as a huge solar panel that captures all its energy from light. It is important to note that the zooxanthellae are responsible for the health of invertebrates, need more light than the macroalgae Caulerpa type, Hamel, etc. However, if the invertebrates belonging to a stratum in very shallow reef niche, need secure their zooxanthellae need light intensity much higher than if medium or deep water. The type of pigmentation that mainly contains the algae determines the kind of light that perform photosynthesis.

When selecting an appropriate spectrum for the lights that illuminate the aquarium, it is important to note that its spectrum is complete and as level as possible. The peaks in the yellow zone, green and orange favor the appearance of ground cover and filamentous algae. Many is the importance of light for all invertebrates with zooxanthellae and macroalgae. Let that light behaves like the energy that makes these living beings are just living. However, it is very vague and unclear about the interdependence of reef fish with the light spectrum and intensity right. You can reach the conclusion that inadequate as fish do not carry the potential for photosynthesis, light is not a factor that directly involve them. Nothing is further from the truth. The fish reef is a living being who is accustomed to the highest levels of stability and fitness in their environment. The coral reef habitat is idyllic in many ways, is a kind of paradise under the sea. In our review of the physical and chemical characteristics of marine habitat, we have demonstrated the extraordinary stability in virtually all the parameters that define the medium. It is not only stable but also the ideals we can qualify. Also contributes to this quality and quantity of light. Because the presence of plankton in suspension is very low, coral waters are remarkably clear. This factor favors the penetration of light is important, not finding it in the way you stop any items. This causes the coral reef is very bright not only determines a dependency factor invertebrate zooxanthellae and macroalgae, but also the reef fish is subject to this standard lighting.

In fact, studies show that the mucosa layer of epithelia of fish is directly related to the receipt of the proper light by the fish. In fact, the fish under the right conditions and natural light that is continually secreting mucus that constitutes the first barrier between the external environment and your body. In fact, when the mucosal barrier is in perfect condition, all the external conditions (external parasites, bacterial outer, etc) are difficult to penetrate, if not impossible. This fact is demonstrated by studies and practices by collection firms to large-scale fish that do not turn off the lights during the few days that keep the fish at your facility before selling it. By simple statistics have come to see that while the fish is illuminated 24 hours a day, like illness or Cryptocarium Oodinium appear more difficult and less virulent. Of course, this practice is not recommended for the amateur, as the fish kept for a long time with the light on can become ill from stress. On the other hand, adequate quantity and quality of light you get the fish on the reef, serves to synthesize vitamin D from the provitamin that purchased food.

Besides the effect of light on the mucosa of the fish, we must take into account another important factor. Although it may seem a little forward, we can say that the tropical marine fish has a psychology rather weak. This psychology is supported by the high standard of quality of life they are accustomed. If the conditions in which they live does not reach artificially high levels of quality, automatically suffers from psychological stress fish, and this is the prelude to the appearance of any parasitic disease, or degenerative. This is of fundamental importance to be taken into account in aquarium keeping coral reef fish community. Do not believe not having invertebrates, fish will not need an adequate range and high light intensity.

It is vital to understand exactly the enormous importance of light to the reef as the base upon which our performance primarily when designing and operating without problems, a marine aquarium.


What is light?
Light radiation is emitted by the excitation of a body as visible energy. This radiation occurs in the visible spectrum, allows us to see objects and colors.
What are the light sources?
The excitement of the luminous bodies can be of thermal origin as the sun, or light emitting source such as lightning or a storm of fireflies. So there are two families of light sources: the incandescence and luminescence.
What are the lamps?
Are bright sources of electrical origin. Filament lamps and halogen lamps produce light by incandescence. Diode, the results from photoluminescence. There are also blended light lamps, that is, produce light by incandescence and luminescence and photoluminescence, such as fluorescent.
The spectrum
The mixture of all colors of the light emitted by a light source is its spectrum. The sun and incandescent lamps produce a continuous spectrum. The discharge of the lamps is discontinuous.
Visible spectrum
Is located from the ultraviolet to infrared, between 400nm and 700nm, the wavelength. They are light blue, light green, light yellow and red light.
It goes the distance the two adjacent crests of a wave measured in nanometers (nm).
Color Temperature
The temperature in kelvins at which a black body (Planck) should be heated to emit light with a certain color stable. In other words, is the numerical expression in degrees Kelvin of the light spectrum. The light yellow or red (hot) has a color temperature of 3000 degrees Kelvin. The light blue (cold) has a color temperature of about 10000 degrees Kelvin. Sunlight has a color temperature of about 5000 degrees Kelvin at the zenith (noon) and about 2000 degrees Kelvin while in the skyline. Knowing the color temperature of light know that it is suitable for use in aquariums.
Color rendering index (ICR)
It is the ability of a light source to reproduce the various colors of the object illuminated by reference to sunlight. Is a scale from 0 to 100. The maximum value is what the sun at 12.00 noon with no clouds.
It is the relationship between light output and power consumption. Is expressed in lumens / watt. This variable demonstrates the ability to emit light visible to humans. Our ability to perceive light is not the same for the entire spectrum. We see a lot more yellow and green light than others. So a watt yellow light seems to us that emits far more light than 1 watt of light blue or red. Can therefore conclude that a more efficient lamp may have less efficiency. Everything depends on the amount of yellow color produced.
Efficiency or luminous flux
Is that proportion of the lamp consumes energy that is converted into visible light measured in lumens. Incandescent lamps have an efficiency becomes very low because most of the energy they consume into heat, not light. The technical limit for measuring the green light is 680lm / w The white light is 225 lm / w.
It is the thread that received a specific surface located at some distance from the source. It is measured in lux. These are the result of the relationship between brightness and distance squared (lm/d2). Can be measured with the help of a light meter.
Incidence is perpendicular to a lumen in an area of 1 square meter. One lux equals 0.0929 lumens.
Is the amount of visible light emitted by a lamp in all directions. A lumen is equal to 10.76 lux.
Half life and the shelf life is the length of the lamps 80% to 80% of their light output and the average is the average length of a certain type of lamps.

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