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Aquarium Light

INTRODUCTION TO FISH TANK LIGHT

Why we need Aquarium Light ?

Basically, aquarium lights primary function is to enhance the appearance of your aquarium. Good aquarium appearance will show the full brilliance of the fishes natural coloring, also dense & healthy aquarium plants. All of that can't be achieved by using just any fish tank light, but it's highly depend on Organisms you want to keep (origin, how many, what type, etc). So, what should we do ?

First, you have to choose your aquarium type before you determine the lighting needs : Plain (fish-only) tank, Aquascape (planted tank), Water turtle tank or Reef tank. Then you should do a little research on the fishes, crustaceans, aquarium plants and other organisms that you choose for their natural lighting needs.

Low light organisms usually come from shaded regions where the daylight is indirect, such as rivers & lakes in the Asian rain forest. High light organisms come from shallow and clear water habitats with 12 hours of direct sunshine.

It's better if you choose organisms that have similar lighting needs because it's difficult to create both intense lighting and shaded areas within a limited aquarium space. Unfulfilment of natural habitat lights can stress your fish and other organisms, affecting aquarium plants' health & growth, also interrupting natural cycles of organisms' behavior. So, our duty is to create aquarium light that similar to their natural habitat.

In natural habitat, there's a day & night cycle. Many beginners often switch their aquarium light on for 24 hours, or only at night! This behaviour disrupts natural cycle and surely stress all your organisms. Since your aquarium will not experience day and night normally inside your house, you will have to create it.
How to determine what type of day lighting that your organisms need will be discussed later in the next tabs, while low-intensity moonlight as night lighting can be fullfiled with inexpensive lunar LEDs. Nocturnal behavior can be observed without switch on the daylight-lamp and disturbing resting organisms, it also promotes good health and natural behaviors like spawning.

Read more about Aquarium Light by clicking the next tabs.

UNDERSTANDING WATTAGE & KELVIN RATINGS

There's a popular formula for determining aquarium lights : 1 watt for 2.5 liter of water. Is this formula true ?

Actually, to determine the need for aquarium lights, we need to consider several factors :

Your tank size | your aquarium types : freshwater / saltwater | your organisms : fish-only / planted / reefs | your aquarium water's depth : shallow / moderate / deep / deepest

Intensity. Intensity is the ability of the aquarium light to penetrate water. This factor is partly determine by wattage, but you have to be careful in choosing the bulbs since different types and brands of bulbs differ in intensity even with the same wattage !. Usually we can see the intensity grades in code printed at the bulbs. Following is the sequence of codes which represent different intensity (from highest to lowest) : D (Daylight), ND (Natural Daylight), WD (Warm Daylight), CW (Cool White), UW (Universal White). Intensity of some lamp-types will decrease after some usage periods.

Color Temperature. Kelvin ratings (K) measure the color temperature of light. Actually the white or yellowish color of the sunshine is combinations of different wavelenghts, but each wavelength has it's own color & temperature. We choose the fish tank light that can give the best color spectrum for your specific aquarium types. Following is the list of color spectrums with their temperatures :
- Red spectrum (<5,000 K) is not for aquarium use, as this wavelenght promotes algae growth.
- Yellow spectrum (5,000 - 6,500 K) lamps are only appropriate for shallow freshwater fish-only tanks.
- White spectrum (6,500 - 10,000 K) lamps are ideal for aquarium plants, deep water fishes and reefs tanks.
- Blue spectrum (10,000 - 20,000 K) lamps are only needed for deepest tanks and organisms, produce very intense blue light and heat.

Remember to always research your intended organisms to learn the habitat's depth and what spectrum ranges have the best effect for them.

LAMP TYPES

INCANDESCENT LAMP

Incandescent bulbs are screw-in filament bulbs that available everywhere and commonly used in homes. They come in different colors and very cheap, but this bulbs is not intended for aquarium use since their spectrum ranges (2700K for normal incandescents and 3000K for halogens) promote algae growth!.

Incandescent bulbs produce a lot of heat compared to the intensity of their output. That's why, they are suitable for reptile terrarium which need heat for basking purpose.

FLUORESCENT LAMP

Linear Fluorescent bulbs are the long round glass tubes that commonly used in homes or offices. They are efficient type of bulb, provide brighter light over a larger surface area than incandescent bulbs. They are commonly used for aquarium purposes, the fixtures are typically included in aquarium hoods becoming part of standard aquarium equipments.

Linear-Fluorescents come in 3 different sizes by thickness /diameter : T12 (1.5"), T8 (1"), and T5 (5/8").

• T12 and T8 bulbs are standard sizes and can fit in the same standard fixtures , they are often referred to as 'Normal Output (NO) Fluorescent'.

Normal Output (NO) Fluorescent bulbs have lower intensity (Wattage), although they have complete range of Color Temperature (<5,000 K until 20,000 K). So they are suitable for Shallow freshwater fish-only tank and Planted tank (Aquascape) with selected Slow-growing aquarium plants which only need low-intensity light to thrive.

• T5 bulbs are shorter, take up half space that T12 occupy, achieving higher intensity in a smaller space, but T5 requires special fixtures (they won't work with your standard fixtures, they need special ballasts and end-caps!).
T5 lighting can be the answer for increasing intensity (higher wattage) that limited by aquarium hoods' space. Higher wattages for intense fluorescent lighting can be provided by T5-HO (High Output) and T5-VHO (Very High Output) lamps.

T5 bulbs are suitable for Light-loving aquarium plants (Aquascape), Saltwater fish-only tank and Shallow reefs tank which need higher intensity aquarium lights to penetrate water.

NOTE : All fluorescents' intensity will decrease after some usage periods. To keep the intensity level, you should replace the aquarium light bulbs after several months of usage although the bulbs are still flamed. It all depends on your flourescent types and daily usage, usually Normal Output (NO) fluorescent will reduce its intensity by 50% after 6 months with 12 hours of daily usage. By the way, check the manuals for details.

POWER COMPACT (PC) FLUORESCENT LAMP

Power Compact (PC) fluorescents are relatively new technology in fluorescents, they take up less space than classic fluorescent bulbs and more efficent (less wattage for producing more intensity).
These aquarium lights need special fixtures to be installed into the aquarium hoods or canopies - 3 types of base : Straight/ linear pin, Square pin & Threaded /mogul base.

Please note that all fluorescents' intensity will decrease after some usage periods. To keep the intensity level, you should replace the aquarium light bulbs after several months of usage although the bulbs are still flamed. It all depends on your flourescent types and daily usage, check the manuals for details.

METAL HALIDE LAMP

Metal halide systems are High Intensity Discharge (HID) lighting systems popular among many aquarium hobbyists.
They generate a large amount of heat & also emit ultraviolet radiation which is harmful to eyes and skin. For this reason, Metal Halide discharge lamps require special handling and care to ensure safe and proper usage.

Metal halide lamps produce the most concentrated, most intense light of any type of artificial lighting. They are ideally suited for deep freshwater planted aquariums and saltwater reef aquariums containing light-loving corals.
A spectacular desirable effect of metal halide lighting is the "glitter effect", which replicates the effect of surface waves reflecting on a reef in a natural environment.

Halides are either:

• Single-ended : Mogul base (screw socket) or G12 base (bi-pin).
Metal Halides are high-powered bulbs that provide highest intensity and color temperature (until 20,000K). They are usually used for aquarium with 60-100 cm depth & hanged above your aquarium with 30-70 cm distance from the water's surface, deeper aquarium needs more intensity (wattage) to penetrate water.

Metal halides are centralized light, it focus in one limited area. You should install several bulbs to cover entire length of your aquarium (a single metal halide bulb lights an area of about 4 square feet, so in a 4' tank you would need 2 Halides).

These high-powered aquarium light bulbs require special ballasts and fixtures, also more expensive than other lamp types. Metal halides' fixtures include cooling fans to reduce the intense heat generated by the bulbs, and hang at a distance (30-70 cm) above the water's surface to avoid overheating your tank.

• or Double-ended : HQI lighting/ R7S.

HQI bulb /R7S is much smaller than screw socket halides and is double ended. HQI systems are relatively new to the hobby and offer many of the same features as conventional metal halide systems, but differ in design. Many of the ballasts for the metal halides can also be used for HQI fixtures.

The HQI bulbs, however, require a system-specific socket & special fixtures with filtering mechanism to block UV light that is produced by them. The fixtures of the HQI bulbs usually include a sheet of glass or plastic in between the bulb and the tank to filter out the short-wave UV. Don't let your skin expose for a long time with this unshielded bulb, you'll get sunburn!

HQI bulbs are commonly available in 150- and 250-watt bulbs.

NOTE :
• Halides are best for deep tanks & light lovers organisms like reefs and aquarium plants.

• Freshwater planted tanks /paludarium usually use 70 or 150 Watts Halides with 8,000-10.000°K for each bulb. For deeper aquarium (>100 cm), intensity should be increased to 250 or 400 Watts.

• Metal halide lighting has several prohibitions like NEVER touch the bulb that is still on/hot, NEVER touch the bulbs directy with your fingers, hot or cold, oil from your finger will weaken the glass.

• The intensity of this aquarium light will decrease by 50% after 1 year with 10 hours of daily usage, to keep the intensity you should replace it after 12 months, although the aquarium light bulbs are still flame. You can use aquarium light timer to schedule your metal halide lighting promptly.

LED LAMP

Usually, LED light is used as an add-on to an aquarium light (for night lighting /moonlight, add a shimmering effect and enhance color).
Now with advances in modern LED lighting, they are intended for serious reef / planted aquarium lighting.

Some benefits of LED lighting :

• High Efficiency. Energy efficient LEDs use less than 50% the power of a traditional fluorescent fixture. 1W white LEDs provide powerful daylight lighting. 60 mW blue LEDs provide lunar lighting for nocturnal viewing and consume less than a tenth of a watt. LEDs can provide up to, or in excess of 50,000 hours of life. The LED lights may remain operational for as long as 100,000 hours, at a decreased luminous output.

• Cooler Running. It runs at a warm temperature rather than very hot which is common with most other inefficient plant lights. Not only do the LEDs generate less heat, but they also dissipate their thermal energy back into the mounting fixture. Most traditional light bulbs tend to dissipate heat from the front of the bulb, and out into the surrounding atmosphere. This more controlled running temperature reduces water evaporation and keeps rooms with tanks and plants from getting uncomfortably hot in the summer months requiring aquarium chiller /additional air conditioning. They save electricity dual fold.

• Lighting Start-Up and Cool-Down. LED lights respond instantly, and do not require a warm-up period. In the event of a momentary power failure, the LEDs will resume normal operation the moment that power is restored.

• Solid State Lighting. Unlike metal halides, LED lights do not feature a gas, operating under extreme pressures, at very high temperatures. Instead, the LED lights contain a solid state lighting element, eliminating several risk factors associated with high pressure gases. Solid state lighting has advanced dramatically over the past several years, and has become the industry standard for a variety of lighting applications.

• LED Beam Angle. LED lights feature superior directional characteristics, the narrow beam angle featured on many LED lights provides illumination within the intended areas only. Not only does this reduce light pollution, but also promotes higher overall system efficiency.

ACTINIC FLUORESCENT LAMP

Actinic light is not just a blue light. These aquarium light bulbs produce only blue spectrum of the daylight which can penetrate deeper water, but not too deep since this aquarium lights are not very intense (it is not Kelvin rated, but measured in nanometers -420nm or 460nm).

This fish tank light is crucial for reef tanks, the light is absorbed by corals and other invertebrates, also needed for water plants' photosynthesis. This aquarium light bulb can fit in standard fluorescent fixtures and it usually combines with daylight fluorescents as suplementary.

REVIEW OF AQUARIUM LAMPS / SUMMARY

Aquarium Lamps	Color Temperatures	Intensity	Tank Types	Pros	Cons
Incandescent/Halogen	2700-3000k	Lowest	Reptile terrariums	Cheapest, ubiquitous, varying colors	Color spectrum encourage algae growth, inefficient (low intensity-high heat)
Normal Output (NO) T8 & T12 Fluorescent	5500-10000K & actinic	Low	Shallow freshwater fish-only tank, Shallow /low-intensity Aquascape	Cheap, easy to find, varying types/colors/effects	Take up spaces, might not penetrate deeper water
T5-HO & T5-VHO Fluorescent	5500-10000K & actinic	Moderate-High	Aquascape, saltwater fish-only, shallow reefs	Smaller & Brighter than NO Fluorescents.	Need specific fixture, shorter bulb's life
Power Compact (PC) Fluorescent	5500-10000K & actinic	Moderate-High	Aquascape, saltwater fish-only, shallow reefs	Smaller size, moderately priced, long lasting	More expensive than NO fluorescents
Metal Halide & HQI	5500-20000K & actinic	Highest	Aquascape, Deep reef tanks	Best for deep tanks and light lovers organisms	Relatively expensive, need experience to install, not for beginners

CHOOSING AQUARIUM LIGHTS

After some readings, it's time to choose your proper aquarium lights. Remember to choose the best color spectrum (Kelving rating) for your specific aquarium types and the right wattage (intensity) to get the most efficient & effective aquarium light.

These are some commonly used general guidelines for planning your aquarium lights :


Tank Types	Wattage (Intensity)	Kelvin Rating (Color Temperature)	Aquarium Lamps	Descriptions
Fish-only tanks	minimum of 2-3 watts per gallon	5,500 - 10,000K	Normal Output (NO) T8 & T12 Fluorescent T5-HO & T5-VHO Fluorescent Power Compact (PC) Fluorescent	Normal Output (NO) T8 & T12 Fluorescent Lamp might be enough for shallow freshwater fish-only tank. Saltwater fish-only tanks need more intensity than freshwater, use higher intensity bulbs like T5-HO & T5-VHO Fluorescent or Power Compact (PC) Fluorescent Use additional actinic bulbs for deeper water (more than 20"), especially for saltwater tanks
Aquascape	minimum of 4 watts per gallon	6,500K to 18,000K	Normal Output (NO) T8 & T12 Fluorescent T5-HO & T5-VHO Fluorescent Power Compact (PC) Fluorescent Metal Halide & HQI	Normal Output (NO) T8 & T12 Fluorescent Lamp might be enough for Shallow Planted tanks or Aquascape with selected Slow-growing aquarium plants which only need Low-intensity light to thrive. Deeper tanks need more intensity, BUT Check your aquarium plants' origin first, some water plants that come from shaded regions, only need Low-intensity light !
Reef Tanks	minimum of 4-6 watts per gallon + actinic	9,000K to 20,000K	T5-HO & T5-VHO Fluorescent Power Compact (PC) Fluorescent Metal Halide & HQI	T5-HO & T5-VHO Fluorescent or Power Compact (PC) Fluorescent are only for shallow reef tanks Increase intensity to 8-12 watts/more per gallon for deeper water or for reef tanks containing Coral, Anemones, or Clams

Most of aquarium hobbyists agree that 10,000K aquarium lights are the all-around safest choice for any tank. The color temperature provides an excellent crisp bright white that looks amazing for the best viewing.

CONCLUSIONS

Determine your aquarium lights' need based on your specific organisms and tank types.

Most of aquarium plants come from tropical regions where the sun shines constantly for 12 hours a day. But it doesn't mean that we have to switch the fish tank light on for 12 hours. In nature, not 100% of sunshine can penetrate the water - some are reflected by the water's surface, it depends on when & where the sun in horizon which creates different angles. In other words, you only have to switch on your aquarium light for 8-10 hours a day continuously.

Use the right Intensity (Wattage) & Color Temperature (Kelvin ratings) for your organisms, low intensity light can not be compensated with longer illumination than it should !

Balancing fish tank light, CO2 and nutrients is important for aquascape. You can read more about it in our Aquascape's Digest article.

Lunar lights are also important for day & night cycle. Lunar LED lighting provides little illumination, usually it emits blue or white lunar lights. Proper day & night cycles provide the best conditions for a thriving aquarium and you better use an aquarium light timer.

Remember the first rule of choosing fish supplies is : Buy products from trusted and reputable brands, it will save you from headache later.