The purpose of this article is to provide basic answers to the most common questions asked about choosing lighting in both fresh and Saltwater Aquariums, with emphasis on beginners, but also with suggestions and resources for much more advanced reef saltwater and planted freshwater aquarium keepers.

We include a suggestion chart at the end of this article which includes recommended wattage per type of light used.

This chart includes low light planted freshwater aquariums to advanced reef marine aquariums.

Much of this information is courtesy of: Aquarium Lighting

Lighting is an important consideration for both freshwater and reef aquariums. It can make a difference on how natural your aquarium appears, as well as brown diatom algae is often a problem in established FW tanks with poor lighting.

There is also some evidence (not conclusive) that good lighting aids in correct Redox which is a water parameter that has a definite effect on fish health. Human studies in lighting shows that lighting that has the same optimal PAR & PUR required by photosynthetic life is beneficial for human health, so extrapolating this to a fish only tank is rather logical.

Besides that, plants, reef, coral, etc, need proper lighting to survive.

For these reasons, obtaining the best light your aquarium keeping budget can afford is highly recommended. This admittedly can be confusing with the plethora of new lights now available on the market, many of which having low energy efficiency and poor PUR, especially with LEDs sold at many discounters.

Advertising slogans also confuse or convince buyers of certain qualities.

An example being a brand advertising "what corals crave" seems great but when we look into the science of lighting including the spectrums at the depths of many of these corals, we quickly find this particular light might be what people crave in coloration but is far from what corals crave.

Worse, when we look at the efficiencies of such lights, we find that the input wattage needed for output PAR is often half that of better LED lights.

Of late many if these heavily marketed lights are now failing at higher percentages than the better built LEDs such as the AAP AquaRay line.

Recommended reading about the importance of PUR in aquarium lighting:

PAR versus PUR in Aquarium Lighting; Freshwater & Saltwater

What type of lighting is right for me and my tank?

This depends on many things, such as;

Tank size

Setup

Species

Budget

Once you finish determining the above aspects you are ready to look at different types of lighting. There are several different types such as SHO (Super High Output) LED, T-2, etc. Please see below.

T8

Even though the watts are higher on the T-12, the T-8 is more efficient with less wattage. The T-8 is the more common bulb/lamp size in many basic aquarium lights.

For the average aquarium keeper, the T8 is still a good choice.
The Hagen AquaGlo is a good example of a basic, but useful T8 aquarium light for freshwater fish aquariums. 

T12

The main caution to the use of these fixtures for aquariums, is the use of shop lights as an inexpensive alternative to many aquarium lights. A 4100 K cool white shop light is not going to come close to a 6400 K daylight lamp that is of peak PAR efficiency, even if you match lumens.

T5

The T5 has become very popular among both plant keeping freshwater aquarists, and reef keepers for good reason. They are compact, come in many varieties and high lumen per watt outputs. As a broad generalization, only requiring 2 to 4 watts per gallon for more shallow planted/reef applications depending upon tank depth and other factors. While the T2 is the latest in straight tube fluorescent lights, the T5 still is better suited for aquariums over 20 inches in depth.

The T5 is a good choice for more advanced planted freshwater and reef saltwater aquarium keepers, but are also considerably more expensive than traditional T8 lamps/lights.

The Aqualine 6700K is a good example of planted aquarium T5 while the Coralife and Helios are just a couple of distributors of Reef Capable T5 lamps/lights.

T2

These fixtures are the latest fluorescent technology yet. HOWEVER the low cost LEDs that have flooded the market has killed the manufacturers of these lights, despite the fact these T2s actually had a higher energy input per energy output of many of the cheap discount LED [but not the premium models such as the AAP AquaRay]

The T2 measured only 7 mm and allow for several bulbs in a small space. A 13 watt 20 inch T-2 Bulb (6400 K) produces 950 lumens which is 73 lumens per watt with low wasted green/yellow light energy that is often found in other Power Compact Lights. As little as 1 to 1.50 watts per gallon for a planted aquarium is all that is needed from these T2 Lights! These fixtures have useful linkable, and rotating lens features too.

The T2 could be an excellent choice for a beginner freshwater aquarium keeper looking for a better light than the traditional T8, that also is less expensive than most T5s (with more light output per watt consumed).

One especially nice feature of the newest generation T2 (302 model) is the built in directional swivel reflector. This makes retrofitting out old T8 fixtures easy as everything old can be removed then replaced with this compact, yet complete and efficient T2 light fixture.

The T2 can also be an excellent planted freshwater light when the correct number is used per the aquarium size (best results are found in aquariums under 20" in depth). Even saltwater aquariums up to basic reef tanks can utilize the T2 light.

The picture to the above demonstrates an 8 Watt T2 over a 14 gallon nano planted aquarium.

The picture below is a combination picture of a very lush 10 gallon aquarium lit only by T2 Aquarium Lights as well as atop view of a 10 gallon tank showing how simple it is to tie two T2 lights together for extra lighting with the parts included. 

PLEASE NOTE; The manufacturer of the T2 has become a casualty of the shrinking professional aquarium industry and is no longer manufacturing this product.

See this web page for American Aquarium T2 Lights:

T2 Aquarium Lights, Lighting (discontenued)

VHO

This stands for "Very High Output". These come in T-5, T6, thru T-12 standard fluorescent tubes.

The new Helios & other VHO Power Compact Fixtures come in a variety of sizes with outputs up to 180 watts out of lamps under 40 inches in length, which rival many Metal Halide (although not in depth penetration).

CFL

This stands for "Power Compact" or "Compact Fluorescent Lamp (light)". These bulbs come in straight pin arrangements, square pin arrangements, and the self ballasted standard incandescent fixture "screw in" type. These bulbs are similar to T-5s and have about the same lumen per watt output (generally around 60 lumens per watt).

The "Screw-in" CFL is a good choice for beginners looking for a better light that can be used in a fixture that normally utilizes incandescent light bulbs.

The lamp pictured to the right is a good example of a screw-in CFL that is also planted aquarium capable if the proper wattage per tank size is utilized. As an example, this particular light would work well for a medium to some high light planted 5 gallon aquarium [2 for a 10 gallon, 3 for a 15 gallon, etc.].

These are also quite inexpensive at less than $6 for a 6500K model.

A good example of CFL lights can be found HERE:

Aquarium CFL lighting

SHO

A newest high output variation of the Power Compact that is much more powerful as per useful light energy produced.

As well, the SHO can be used for reef aquariums as an addition to LED or Metal Halide.

The SHO Light is currently sold in a self ballasted PC bulb/light. The 105 Watt SHO Daylight bulb puts out 6300 lumens and is comparable to a 525 watt Standard bulb.

The SHO is generally the best light other than some high end LEDs for planted freshwater aquariums over 40 gallons. The SHO is an excellent choice for larger planted freshwater aquarium.

Probably the only negative to the SHO light is it is not an "out of the box" light and generally requires some DIY skills to install. HOWEVER if you have reasonable DIY abilities, this newer, much more powerful version of the CFL is well worth it in both cost to own and phenomenal results!

One source for SHO Lights can be found:

Aquarium, Hydroponics SHO lighting

Metal Halide

Metal Halide was considered the "King" of reef aquarium lighting due to depth penetration, output, spectrum, and over all beauty and amount of coral life they help support, making most corals "pop" with life.

Aesthetically speaking, the Metal Halide is hard to beat. However, the newest high output LEDs are now taking over the MH and are beginning to surpass MH for Reef aquariums. LEDs have been proven to surpass MH with plant growth in nursery/hydroponics environments.

One study/test shows a 12 Watt Full spectrum LED producing better growth than a 175 Watt MH of the same type!

That said, for tanks over 30 inches in specimen placement, the Metal Halide is still generally the best available light, especially when used in light combinations that include 20,000K, with other popular Metal Halide Kelvin color temperatures being 10,000K, and 14,000K.

Further Reference: Aquarium Lighting; Metal Halide

LED

The high quality LED lights do not have the heat problems of other lights, often last 50,000 hours, produce less of the lower efficiency yellow/green spectrum light (in aquarium adjusted configurations), and are very compact. In fact, this more balanced PUR & RQE ["photosynthetically useful radiation" & "relative quantum efficiency"] light in many, all 'high end' emitters used by various LED Kelvin lights (whether 6500K or 14000K) often make the LED look less bright to the human eye, when in fact the opposite is true as per useful light energy (aka PUR).

LED Lights can used from anywhere from basic fish aquariums to advanced planted freshwater and advanced reef aquariums, however there is a wide variance in light output of emitters, with some LED fixtures requiring 3 times as many emitters to produced the same PUR light energy required by the best patented LED fixtures.

Be careful with LED lights sold for advanced planted or reef aquariums that only promote their PAR capabilities, as while PAR is certainly a useful and measurable method for determining LED lights, it has many short comings too as one light can have a much higher PAR than another yet be much lower in the also important PUR.

Many forums and blogs often promote professional looking graphs from a self proclaimed LED expert whose credentials are actually marketing. These graphs totally ignore PUR, which in this websites view is a dishonest form of manipulation/lying via omission of critical information.

Another concern since even some of the lower end aquarium LEDs such as the "Current Satellite", "Fluval LED", and even the "Finnex" can keep a healthy planted aquarium, is water proof/resistance capabilities. Since an Aquarium LED is not a light in the traditional sense, but instead is an electronic device that emits light via light emitting diodes, it is important for long life, risk of fire, or accidental dropping in the water to have a IP67 rating or more, yet almost all LEDs have an IP66 or lower, which is reflected in warranties of as low as 6 months (however the Fluval while still utilizing low cost emitters and has low output per input energy, does have a IP67 water proof rating).

Suggested Reading for more advanced aquarium keepers; both are excellent MUST READS!:

#LED Aquarium Lighting, Lighting

#PUR vs PAR in Aquarium Lighting

Examples of good to excellent LED Fixtures include the EcoTech, Aqua Illumination, and the AAP AquaRay/GroBeam LED Aquarium Lights

Suggested Resource for the BEST Aquarium LED Lights [by best, longest warranty, best build, optimized PUR, and the highest PUR per watt with the least wasted energy often due to the need for cooling fans]:

AAP Premium Patented LED Aquarium Lights, Lighting

As of 2017, Beware of an unscrupulous wholesaler, selling retail out of the home of a staff member with an official sounding name and URL.

The best and ONLY true professional full service online retailer of AAP AquaRay Lighting is the above cited resource!

AAP has been selling these these premium highest efficiency LED lights since 2008 and know what they can and cannot do, unlike this official sounding parasite clearance retailer [who will not be around to service your light if needed once they have cleared out their stock].

The 55 gallon planted tank below is lighted with GroBeam 600 LED fixtures:

Below is a composite picture displaying the high PUR AAP GroBeam 1500 over a 55 gallon hex aquarium, as a well as an advanced reef aquarium lit by a combination of AAP Ocean Blue NP 1500s and AAP Reef White NP 2000.

The AAP GroBeam LED would be this author's recommendation for a freshwater aquarium based on these criteria:

Highest Efficiency as measured in output PAR mml to input wattage of any LED aquarium fixture

Premium licensed Cree emitters that are specifically designed for the daylight 6500k needs of most freshwater and specifically freshwater planted aquariums.

The highest PUR and RQE which translates into quality of light per photon of light emitted.

Highest light output efficiency per input watt of energy consumed. No need for fans as these LEDs produce less wasted heat energy

The best warranty; Most freshwater aquarium LEDs are 180 days to 3 years max, and even then only for a repair that can take some time. The GroBeam is 5 years with full LED fixture replacement.

"Water Resistant Design (IP67). Highest level of protection, NO OTHER Aquarium LED has this rating, the next highest is IP66. Protected from dust and against the effects of immersion in water to depth between 15 cm and 1 meter "

Quoted from AAP AquaRay LED Aquarium Lights/Lighting

Since an LED light is essentially an electronic device like an iPad that is placed over an aquarium, why use one that does not have such a rating, this makes little sense?

WARNING:

LED lighting has really exploded upon the aquarium industry as of 2013 and beyond, with many extremely poor quality LED fixtures made in China being dressed up with nice bells and whistles, but in reality have no more essential "Photosynthetic Useful Radiation" [PUR] than a flashlight you can purchase at Walmart for $3.

It is also worthy of note that most of these "Johnny come latelies" have very low efficiency when measures output PAR against input wattage. Often this lack of efficiency is 1/6 resulting in much more energy used for the same results; example AAP Reef White NP 2000 LED compared to SB Reef Light LED

It is important to note that if one simply daisy chains LED emitters such as the Current Satellite, Fluval, Finnex, and other poor PUR LED lights, it is impossible to properly regulate voltage which results in poor "quantities" of output energy [PAR] along low "quality" of output energy [PUR].

As well most of these low cost copycat LEDs flooding the market via PetCo, Amazon and other low end retailers utilize very low cost, low efficiency warm white emitters and then add green, red and blue emitters in a misguided attempt to balance these lights. But in reality these lights end up with much of its light energy [photons] in spectrums of lower efficiency for photosynthetic life.

In the end, if you purchase one of these low end LEDs all you are doing is buying a light with some nice appearances, that will in fact still generally grow plants/corals, but at a higher cost of input energy for per output energy.

Problems include less natural light and very short lifespan when compared to a well constructed LED with a warranty to back it up.

Failure of fans, causing heat damage is common, even some of the brands many consider more premium have heat issues that have damaged the light resulting in premature failure.

An example would be the "Build My LED" light!

Frankly, even a fluorescent light would have cost less, likely have a better light spectrum, and last longer. If you budget is tight, consider a SHO over many of these LEDs flooding the market!!!

Here is an excellent video that shows the aquarium keeper what they get as per waterproofing with the better LED fixtures over the common Finnex and others marketed via discounters, Amazon, etc.:

The other issue becoming more apparent is poorly researched Internet articles that are nothing more than "copy and paste" as well as YouTube Videos that also CANNOT even get some of the basic facts right/correct.

A good example is a YouTube Video where the narrator attempts to call out well documented articles that are well backed up with references, yet cannot even get some of the basics correct such as the FACT there is a quality of light and the long established FACT warm white lighting is much less efficient, yet this is what he recommends!

Further Reading/Documentation: PUR or RQE, YouTube Video Fail- Guide to lighting a planted tank

Freshwater Aquarium LED Clip-On LightIF LOW COST LEDS ARE WHAT YOU SEEK, do not fall for the slick marketing of these discounters and purchase an LED that is marketed just as that!!

The AAP "Aqueon Freshwater Aquarium LED Clip-On Light" fits the bill providing excellent lighting for community or low/medium planted aquariums up to 20 gallons or even more when multiples are used.

Resource:

AAP Freshwater Aquarium LED Clip-On Light

There is a common belief that moonlight should be "blue" when in truth all the moon does is reflect diffused sunlight back to the earth. Dust or moisture can affect the color spectrum seen by the human eye as well, which often make the light appear blue. This means that a dimmed/diffused daylight is a more accurate production of moonlight.

These are very popular for marine reef aquariums for both a low level "night light" and for simulating moonlight for corals and coral propagation. Where some of the misinformation comes into play is that many will state that fish and coral need these lights, of which there is absolutely no scientific proof.

Further Reference: Aquarium Lighting; Lunar

Maintenance is dependent upon what type of lighting you have. However, any type of lighting will need proper ventilation, placement, and cleaning. Proper ventilation is one of the most important aspects, as humidity will ruin any electric device.

Even LED's that are pretty water resistant can have their delicate circuitry and fans damaged by humidity (not all LEDs have fans). Having an open top, or open back, is not good enough, you must have proper ventilation.

Lighting must be placed properly to avoid any possible problems with water/ humidity, and also for the proper light spread.

Regular cleaning of your lights is also a necessary maintenance procedure. All lights must be wiped down on a regular basis to be sure there is no moisture, calcium, or gunk, build up on the unit/ bulb. (I use rubbing alcohol to clean my T2's, and it works great!)

Please Reference: Proper LED Ventilation

Simply put, fluorescent aquarium lights last about 8000 hours. HOWEVER the phosphors that provide the important spectrum many plants need and to a lesser extent newer science shows fish benefit too, are 50% spent in half these hours (4000).

For this reason, for best results an aquarium fluorescent light should be replaced every 4 hours, which generally works out to 1 year under normal use.

This would include the T8, T5, T2, SHO, VHO, CFL (although the T2 can last 10,000 hours)

Premium LED Lights, such as the AAP AquaRay can last up to 50,000 hours and do not suffer from the loss of phosphors since LED lights are not lights in the sense of most persons think of such as fluorescent and incandescent lights. A LED light uses semiconductor technology as its light source.

No, lighting does not have to be difficult. It honestly depends on what type of setup you have, and what type of lighting you have chosen. Some lights are more difficult than others and this is where research comes in. Make sure you know what type of lighting would work best for your application and also what kind of maintenance, upkeep, and difficulty it entails prior to purchasing.

While this is an outdated rule, we can still use this as a rough guide as per specific lighting types: