The type of aquarium light you choose really depends on the job you have to do, and before you buy, you should consider the pros and cons of each to see which one is best suited for your proposed setup.
Choosing The Aquarium Lamp
There are several factors to consider when selecting the most suitable light for your aquarium. First of all, is the tank freshwater or marine, and will it house only fish or will it also have plant life/corals?
Next, consider the size of your aquarium. In addition to length, keep in mind that deeper water may require brighter lighting. In this article we explain better the ratio of lumens per liter in the aquarium.
Lastly, your budget will play a huge role in which type you choose. What may seem like a more expensive purchase to start with can end up saving you money in the long run when comparing running costs.
It is important to remember that when setting up an aquarium, we strive to accurately simulate the daily conditions in which the tank’s inhabitants would typically live in the wild.
Naturally, the aquarist wants to illuminate the tank to see their fish, and while it can be as simple as providing set times of day and night (light and dark) for a fish-only aquarium through a general purpose aquarium light, Specific light spectra are essential for the continued health and growth of plants and corals.
It is also important to control the amount of light the tank receives, if too little is provided, plants and corals can die, and if too much light is provided, the aquarium could become overgrown with algae. Generally, around 8-10 hours of light per day is recommended for freshwater planted aquariums and a photoperiod of 10-12 hours for reef setups.
Color temperature is a term often encountered when choosing lighting for specific aquariums. During the 19th century, British physicist William Thompson (Lord Kelvin) devised an absolute thermodynamic temperature scale.
During his research, he heated a black-body radiator which first began to glow red, then as the temperature increased it turned yellow, finally producing a bright blue-white light at the highest temperature. These light colors always follow a pattern and occur at specific temperatures, which are expressed in degrees Kelvin (K).
Light is made up of seven colors and sunlight (measured at 5500K) emits all seven colors, making the light appear white.
Lights with a lower Kelvin rating, eg 4000K, give off a reddish hue (long wavelength/less energy). And those with a higher Kelvin rating, eg 7500K+ appear blue (short wavelength/high energy). This means that lower color temperatures indicate ‘warmer’ light, and higher color temperatures equate to ‘cooler’ light.
light and water
To further complicate matters, the light also changes the further it penetrates the water, particularly noticeable in the deepest regions of the ocean where only a few colors of light will reach the bottom.
This is because when light travels through water, the longer wavelength light (red) is absorbed first, and the shorter wavelengths (blue) travel much deeper and scatter in different directions, which makes the water appear blue.
There have been many advances in aquarium lighting technology in recent times, helping us to replicate specific lighting conditions with ease. Here we detail the pros and cons of each type of aquarium light in order to help you make an informed decision when buying.
Fluorescent aquarium lamp
Undoubtedly still one of the most common types of aquarium lighting, the fluorescent lamp is available in the form of long tubes, either T8 (older style, larger diameter) or T5 (newer, narrower diameter).
The tubes come in a variety of lengths and fit inside the top of the tank. Its output can be further enhanced by the use of a reflector placed behind it to angle more light into the aquarium.
Fluorescent lighting is available in many different wavelengths, including warmer (reddish) light to show the colors of tropical fish, daylight simulation bulbs (good for both growing plants and displaying fish), specific plants (intended for highly planted aquariums), and marine bulbs (blue).
A typical ‘full spectrum’ aquarium lamp will be rated between 5000-6500K and is ideal for planted aquariums. T5 bulbs have an advantage over older T8 equivalents in that they are more compact, give off brighter light, and last about 25% longer.
This type of lighting is cheaper than other types, readily available and available in many different spectrums to suit individual needs.
The downsides are that fluorescent lamps give off heat (so a chiller may be needed to maintain the desired water temperature) and these bulbs don’t last as long as newer light sources such as LEDs.
Keep in mind that while aquarium lamps may still light up well after 6-12 months, they may not be emitting the correct light spectrum and will need to be replaced if you want to maintain optimal conditions within a tank containing plants. or corals.
LED type aquarium lamp
LED (light-emitting diode) lighting is relatively new to the aquarium hobby, and because of its many advantages, it is quickly becoming the lighting of choice for most aquarists.
The LED aquarium light generates penetrating light with a uniform color spectrum throughout its lifespan, a great benefit over fluorescents that will require frequent replacement due to color change after several months.
Aquarium LED lights are compact and available to fit any aquarium, from small clip-on units for nano tanks, to simple thin strips (solid or flexible) for standard aquariums, submersible spotlights, and even modular mosaics for larger displays that can be used as fixtures. They can be suspended above the tank and placed adjacent to each other to form giant LED panels.
Although the initial price will be higher than that of fluorescent tubes, the low operating costs will more than make up for this in the long run, particularly since the LEDs will not require periodic replacement. Most units claim to work for about 10 years.
The LED aquarium light does not generate heat, so you do not need to use a chiller in the aquarium, and many models can be controlled remotely. Another advantage is the beautiful glow effect that LED lighting creates, similar to natural sunlight streaming through water.
LEDs are available in a variety of colors to suit all types of aquariums including marine reef, planted and fish only. If you are interested in lighting natural plants, you can visit our articles on led screens for planted aquariums.
metal halide lighting
Metal halide lighting produces powerful illumination through an electrical arc passed through a bulb containing a gaseous mixture of mercury vapor and metal halides (compounds of metals with bromine or iodine).
This high intensity light penetrates deep into aquariums giving an LED-like glow effect, is long lasting and has low running costs.
However, the bulbs and their units can be a bit expensive compared to other types of lighting, and since this type of lighting generates a lot of heat, a chiller may be needed to keep the water temperature at an acceptable level.
Metal halides with a color temperature of 5500-6000K replicate natural sunlight, perfect for freshwater planted aquariums. Bulbs with a color temperature rating of 10,000-20,000K are ideal for marine reefs as they promote rich coral growth.
Most metal halide units will need to be suspended from the ceiling above the tank, although some smaller units come with accessories that allow you to place the unit on top of the aquarium.
In the market you can find a wide variety of lamps for aquariums, if you are still not very clear about the issue of lighting in the aquarium, we advise you to take a look at our guide on light in the aquarium.