Big NO for natural sunlight – Aquarium

By reefspecialty, April 4, 2015

Beginners might think lighting an aquarium is just to help viewing the fishes clearly and also to give an aesthetic look for your tank. But no, it is not the only reason. Lighting an aquarium is very important for the well-being of the species in the tank. You should take extra caution while choosing the light for your aquarium. After deciding what species you are going to grow in your tank, choose the light type that best suits them. This article explains about various types of lighting available for aquarium and its features.

By going through this article, you will get an idea on what type light can be chosen for your aquarium and which lighting will help for a healthy life of your pet.

Why not natural sunlight?!

While thinking of lighting your aquarium, why naturally available sunlight wouldn’t be a best option? People living in Tropical regions can rely on sunlight for their aquarium. But for people in other regions where day light is very short for most of the months in a year, this can’t be a better option. If you are choosing natural sunlight as your aquarium’s lighting source, then you have to install an effective cooling system, which would require more investment. Also, you can’t keep the aquarium in a place where you like to keep it, as you need to set it only where sunlight is available. And you can’t enjoy the beautiful view of the tank in evenings, due to darkness. For such reasons, people will mostly opt for artificial lighting.

Incandescent LightAquarium Lighting Products

Incandescent light bulbs are the least expensive light fixtures and most of the basic small fish tank (10 to 20 gallon) will come with this type of fixtures. But unlike other types of lightings, the incandescent lights emit more heat which leads to difficulty in maintaining the tank’s water temperature. Also, these types of bulbs will consume more power and does not last for a long time. So, you have to keep changing the bulbs often and pay high power bills. Considering these facts, people will quickly replace incandescent bulbs with other reliable type light type so that they can save money and have healthy environment for their species.

Fluorescent Light

Fluorescent lightings are the most common type of lighting used for most of the aquariums. These are little expensive when compared to incandescent bulbs. But while thinking of the reliability, fluorescent lights last longer. Kelvin (K) is the scale for measuring color temperature. Fluorescent Freshwater Aquarium Lighting Productslights are available in different intensities. Let us see about some of them here.

  • Normal Output Fluorescent Light:

Normal output (NO) or standard output fluorescent lights are the best choice for starter tanks. These are affordable and can be used in both freshwater and salt water fish only tanks. Also, this type of light is easy to use and consumes less power. These lights are available in 20 to 40 Watts range and color temperature ranges from 5,000 K to 10,000 K.

  • High Output Fluorescent Light:

High Output (HO) light is also known as, T5 – HO light is suitable for lightly planted aquariums.  This will not emit more heat. These are comparatively expensive than NO, but produces twice that of brightness and occupies very less space as they are very thin. Also, HO lights lasts longer that NO type lights. This type of lights come in 30 to 60 Watts range and color temperature ranges from 6,000 K to 11,000 K

  • Very High Output Fluorescent Light:

Very High Output Fluorescent lights (VHO) are better choice for aquariums with dense plants. It can also be used for huge aquariums and reef tanks. But, these types of lights are very expensive. It
requires additional ballasts or fixtures for proper functioning. And chillers also have to be installed, even though VHO often comes with inbuilt fans. All these factors let aquarists to think of other choices of light for their aquarium.  These types of lights are available in 80 to 160 Watts range and color temperature ranges from 10,000 K to 20,000 K.

  • Compact Fluorescent Light:

Compact Fluorescent lighting, also known as power compact lighting is the next generation inSaltwater Aquarium Lighting Products fluorescent lighting. This type of light is suitable for both fresh water and salt water aquariums. Power compact fluorescent light is capable of providing bright light nearly 2 – 3 times that of a Normal Output (NO) light of similar length. Also, the power compact lights are smaller in size. So, you can install more number of bulbs in the hood and make your aquarium look brighter. This lasts twice that of standard output fluorescent lights thus saving the money. These are available in two types of pin base styles. One is square pin base and another is straight or linear pin base. So, you should make a note of it while buying replacement bulbs for your aquarium. However, based on the number of bulbs you use, heat produced might increase significantly. Some of the power compact ballasts come with in-built fans. But, installing cooler fans or chillers have to be considered based on the temperature increase in the tank water. Power compact lights are available in 10 to 130 Watts range and color temperature ranges from 5,000 K to 10,000 K.

Metal Halide Lighting

Metal Halide Lighting
or MH lighting are best suited for fresh water planted aquariums and reef tanks halidewith species which require intense lighting conditions. Metal halide lights are available in 100 to 1000 Watts range and color temperature ranges from 5,000 K to 20,000 K. MH lights produce substantial amount of heat. It also consumes more energy and requires special ballasts and fixtures. These factors make the MH lighting expensive.  But, unlike other type of lights, the light spectrum and color rendition of metal halides lights makes it suitable for very large and deeper aquariums. It can penetrate light through nearly 24 inches deep tank.

Metal halides are choice of many hobbyists because it helps to add special lighting effects for their aquarium. Using it you can give spot light effect for corals which requires high lighting and also creates rippling effect on the bottom of the aquarium. Over a time period, metal halide lights starts fluctuating. So, it is advisable to always use metal halide lights with any type of fluorescent light. Fixtures that can hold both metal halide and fluorescent light are available in the market.

LED Aquarium Lighting

LED lighting systems are going to be the future generation lighting system, because of its advantages over other lighting systems. LED lighting is suitable for both fresh water and reef aquariums. It emitsled very less heat compared to Fluorescent and Metal Halide lights. Also, it consumes less power and lasts for a longer time. But LED lights are slightly costly as it is overcoming many disadvantages of other types of lights. The price is slowly coming down as the number of user increases.

LED lights are also called as LED Lunar lights as they are used to simulate moon light effect. They create a cool, night time effect for the species in your tank. Due to their considerable small size, it can be used in many customized patterns. It is available in multiple color spectrums, so you can enhance the look of your aquarium by setting different color combinations of light. You can also use dimmers to adjust the brightness of each light or blend different colors. Dimmers also help to increase the durability of the LED light and save power. Though LED lights do not transmit heat into the water, they send the minimum amount of heat generated upward. This might cause degradation to the LED chip. So, you have to use cooling fan to ensure LED chip is not affected directly by the heat generated.

Points to remember

Apart from choosing apt light for your aquarium, you need to know certain strategies to be followed for better life expectancy of the lights and maintain a healthy aquarium.

Lighting hours:

You should not always keep the aquarium lights on. You have to simulate day light in your aquarium. underwater_treasures_210827That is, you need to keep lights on for approximately 10 to 12 hours during day time and turn it off for rest of the day. This will help to mimic the natural lighting conditions for the fishes or invertebrates in your tank. Keeping lights on over 12 hours per day will increase temperature of the tank water and might endanger the life of the species in it. Also, excess lighting will lead to algae blooms and disturbs the water’s biological balance. To manage this, you can install auto-timer and set it to turn on and off on regular timing.

Changing lights:

Your aquarium lights need to be monitored regularly and changed before it is worn out completely. Because, the color spectrum starts changing while the bulb reaches its end of life. The change in the original wavelength of the lights will result in loosing helpfulness of that lighting for your aquatic species. Instead of waiting till the light completely stops emitting light, consider changing it once in one to two years based on the quality of the light you are using. Also, you should periodically check the ballasts as well. Improper functioning of the ballasts will also affect the light’s functioning. So, if you see any signs of overheating or any other problem in your ballasts or fixture, then it also has to be changed.

Using light meter:

For monitoring the performance of your tank’s lighting system, a light meter can be used. This helps to identify when your light need to be changed. And also, it helps to determine varying light levels in different areas of your tank. So, you can arrange the lighting in such a way that required intensity of lighting is provided for different species in your tank. Most of the lighting meters are less expensive and reef aquarium hobbyists may consider buying one for achieving a lighting friendly aquarium setup.

Acclimatize corals to new lights:

Corals are very sensitive to lighting and other water conditions. Additional care need to be taken while you are switching from incandescent light to fluorescent light or from fluorescent light to metal halide light, etc., in your aquarium. You need to acclimatize the corals to the new lights introduced in your salt water aquarium. Neglecting light acclimatization process will lead to de-coloration or bleaching of corals. When there is a sudden change in lighting conditions, the corals will get stressed and expels “zooxanthellae” (which gives them color), leading to de-coloration.

By following any of the below acclimatization steps, you can make the switching process easy.

  • Initially, do not let the light run for a long time as you were doing before changing the light. As you know, normally 10 to 12 hours lights need to be kept on in your aquarium. But after switching to new type of light, reduce the time to 4 to 5 hours. Gradually, keep increasing the light exposure time by adding 1 hour every week till you reach your normal schedule. Meanwhile, keep monitoring your corals for any signs of stress or color change.
  • If you are using hanging lighting set up, increase the height of the fixture over the tank. Over the period, slowly lower the fixture to the normal position. This might take 3 to 4 weeks.
  • You can also install dimmer to decrease the intensity of the light. Once your corals are accustomed to the new lighting, then slowly ramp up the light’s intensity to normal condition.

Choosing light based on tank depth:

Based on the depth of the tank, you need to choose light system. Deeper the tank, more intense the light should penetrate. For the tanks with live plants or photosynthetic corals, lighting should reach till the bottom surface. The tank might look like fully lit, but required amount of light may not be available till the base of the tank. So, if the tank height exceeds more than 14 inches you need to consider adding extra light or choose higher version of light system.


With a wide variety of lightings available, identifying and choosing the suitable light system for your aquarium plays a vital role in setting up a healthy aquarium. Select proper lighting based on the size, depth, nature of species in your aquarium. And enjoy the pleasure of viewing beautifully lit and healthy aquarium.

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