Further Revised 1/28/16
- LED Overview
- Emitter History
- Useful Light Make Up
- Ways to Measure Output Energy
- Plant Useful Energy
- Corals Useful Energy
- RGB Features
- Watt per Gallon?
- Circuitry & Current Reduction vs. Pulse Width Modulation
- Emitter Combinations versus Specimen Placement
- Additional Benefits of LED Lighting
- LED Light Comparisons/Tests
- Further LED Fixture Emitter Information, Myths
- LED Cautions
- E-Shine (Stark)
- Sky LED, Freshwater Bright, Fluval LED
- DIY LED Light Fixtures
- Basic Mounting Suggestion
- T5 to LED Comparison
- Proper LED Ventilation
- LED Summary
- LED News, Developments
From brand patents/exclusive license agreements, PWM drivers, input/output energy, and more, the science speaks for itself!! The repeated experiences back up the science! Lighting and aquariums ARE science, albeit with art and personal preferences mixed in!
I try and mix simplified science for easy reading along with a lot of practical experience in this article. I cite many other related articles to back up the science and these include articles, which are trusted. Also backed by experienced individuals, which I know as well.
Very limited research in this areas of lighting is being done in regards to aquarium applications. Much of this work is referring to other horticulture as a reference.
If we can figure how to get more usefulness of a light source, we can learn how much is minimally needed, which will allow us to be more efficiently.
Please read ALL my cited references and consider reading my other articles about Aquarium Lighting. They provides some foundation to the hows and whys of this article.
At the end of this review, we should be able to understand these light measures of LED, and which ones are best used for useful light producted by the source. Will will start with the most useful with todays science, and work backwards.
The two most mostly reviewed will be PAR as most important, then Corrected Color Temp Kelivn. The others measures used, but are less useful for understanding usefulness for photosynthesis; will also be review later in this article.
*LED [light-emitting diode] Overview:
This aquarium light type uses semiconductor technology as its light source. A light emitting electrical diode. This is a different technology then fluorescent lighting and how it’s sciences are used are different. Since this lighting type is different in the sense it can pinpoint intensity of light, down to the specific nanometer of energy, this tech has been used to really help understand the photosynthetic process and how certain light (energy) is used by the plant & coral.
For aquarium use, the development of LEDs since 2007 for both reef and freshwater planted, was trying to get a high amount of energy (carried by Photons) into correct wave lengths of spectrum used in aquarium photosynthesis and ultimately being the mose usable light of a emitter [PUR = Photosynthetically Usable Radiation] for whatever photosynthetic organism was being grown.
While nothing about photosynthesis is required to know in order to grow plants, it does help us understand how effectively we are growing and does give an idea of the type of color and energy we can expect from our light source.
The first picture above is of an office with many reef aquariums (which includes stony corals, SPS and LPS) set up with low input energy/high output AquaRay LED lighting systems, please click to enlarge
Please reference this forum post for more about this picture:
For the whole LED fixture as a whole, essentially, the best LED fixtures are NOT aquarium lights in the traditional sense, even the emitters are not a “bulb” as many people think. They are a computer chip emitting frequencies of waves, which happen to end up being visual light we see.
High end LED fixtures use complex circuitry to precisely spread electoral voltage over drivers, which control each emitter. LED lights properly driven will give precise energy quality and not lose or shift energy (spectrum) unlike ALL fluorescent lights.
For other LED fixtures, this statement cannot be made, because emitters are daisy chained together in a shotgun approach to provide output light. These light source are now commonly dimmed, which we will find out if not done properly, it will not be the best for long term use.
For those who are unsure as to what a LED light can do for their reef aquarium or think these are still untested even as of 2015, here’s an excellent newer website documenting the LED Light research at Saint Mary’s College of Maryland by Dr. Walter Hatch, showing better growth, spawning, and more with highly tuned LEDs.
THIS IS AN IMPORTANT READ!
Sustainable Reef- Optimal Growth at Low Energy Consumption
St Mary’s Marine Biology Experiments with LED Lighting
Based on research and interviews, beginning in 2007 [and continuing to improve as of 2015], high end LED aquarium lighting started to become a viable replacement for metal halide in reef tanks under 30 inches and surpass most T5 aquarium lighting as soft and hard corals are able to thrive under the newer exacting high output LED’s.
This is not only due to the excite energy (light) output, but also due to the amount (quantity output) of specific energy frequency of light (photons) LEDs are able to provide for input energy used. LEDs have both quality and quantity light for specific applications we want to use them for.
By this time, many planted freshwater applications were already having success with lamps, such as the 6500K PAR 38 lamps. This needs to not be confused with the low output 3000K PAR 30 sold at places like Home Depot as this simple example makes a valuable point.
See: 6500K PAR 38 Planted Aquarium Lights
Emitters output different frequencies (some visual to the eye) by utilizing certain compounds, which convert input energy into photons (light), which are delivered to the plant.
Some frequencies are more efficiently used by the plant for photosynthesis over others. Photons are the carriers of these frequencies and these frequencies can be more intense than others with more energize movement of the energy. Certain frequencies specifically (and combined, working together synenergetically) are used to provide essential light energy required for certain applications.
For example and only for a second this will become too scientific, how emitter diodes are created can be complex and precision equipment has to be used to compile the light diode. A substrate material is used and layered with other materials, which takes input energy and converts it into light photons, and delivers the output energy through a len.
Infrared emitters use Gallium arsenide (GaAs) and/or Aluminium gallium arsenide (AlGaAs) for its semiconductor material, while Blue (460 nm visually) uses Zinc selenide (ZnSe), Indium gallium nitride (InGaN), Silicon carbide (SiC), and/or Silicon (Si).
Brief overview of aquarium LEDs contrustion: How LEDs work.
“The two pictures above make a real world application point as to the real outcome of light wave lengths.
The first picture to the left displays plant growth with three different light sources, driven at lower and higher PAR values.
It is clear from the graph that the green is 50% less efficient than the red and a whopping 80% less efficient than the blue. So this study somewhat destroys the 30% argument!”
PUR, PAS, PAR in Aquarium Reef/Planted Lighting; LED Wavelengths
Having certain frequencies dialed in intensity [quality and quantity] are important.
One way to think of the high end LED fixtures, not other LEDs, which have more in common with an LED flashlight, these are computers, which emit frequency wavelength needed for tank inhabitants.
[See Proper LED Ventilation later in this article].
Above/left is a hard coral growing out under “quality” LED Lighting
There are different emitter qualities (mix of frequencies) put into lighting fixtures, which we will address. They’re name brand emitters, which are known by many people, because their name is backed up. Phillips, Cree, Osram, Bridgelux are the most common names. It’s typical for larger name companies to have more funding behind their lighting research as well.
Cheaper fixtures will use no name emitters. This can be important to know for a couple reasons. One, there many ways to create a frequency (bins) with a LED. Different emitters can have the same rating, but not have the same quality and quantity of frequency wavelength to create the overall visual/non visual spectrum. 6500K from Cree and it not going be the same frequencies or appear visually as the same as a 6500K from Phillips or Bridgelux. There’s differences in straight 6500K emitters and differences in the overall combination of frequencies/color to make an overall specific Kelvin fixture color rating. [Explained more in the Kelvin Section].
This comes down to cost/budget-supply/demand (marketing & research), of how fixtures are put together. No named emitters are a flag for how quality a fixture will be and what you should expect to pay for it. Different emitter companies will have standards (some patented/specific application agreements or licensing) of how they design their frequencies and also will have different color selections.
These differences will create different quality/quantity of photons in different areas of the photosynthetic spectrum.
Useful Light Make Up:
Here’s a fantastic video describing the Nobel Price Prize idea of how we get the most USEFUL output light energy from a LED input source. This section will accompany the video to quickly understand how we useful light for an aquarium application.
Blue LEDs and Nobel Prize – Sixty Symbols
At the end of trying to understand light energy, It comes back to these terms/graphs, where all have an important role in how they work individually and how together synergistically they make up overall PUR for the application of aquatic plants and reef coral.
–Photosynthetic Action Spectrum– (PAS) An action spectrum is the rate of a physiological activity plotted against wavelength of light, It shows which wavelength of light is most effectively used in a specific chemical reaction (Plant & Zooxanthellae photosynthesis).
Some reactants are able to use specific wavelengths of light more effectively to complete their reactions. For example, chlorophyll is much more efficient at using the red and blue spectrums of light to carry out photosynthesis. Therefore, the action spectrum graph would show spikes above the wavelengths representing the colors red and blue.
–Photosynthetically Active Radiation– (PAR) designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. This spectral region corresponds more or less with the range of light visible to the human eye. New science is exploring more out of this range.
Wiki- Photosynthetically Active Radiation
–Blue light– Generally where we see having the proper (and most intense) frequency of energy delivered by Photons for the photosynthetic process (more intense also is better for penetration, also proper for corals evolved to blue light.
Typical PAR action spectrum, shown beside absorption spectra for chlorophyll-A, chlorophyll-B, and carotenoids
Energy used by Zooxanthellae’s in the full photosynthesis process.
Full Spectrum of the Sun.
Frequency of different energies carried by Photons
Amounts of Red, Blue, and Green (all colors from the Visual Spectrum, RBG are primary colors) mixed together create a white appearance to our eye (explained in Kelivn/CRI), just like if you were to mix all plaint colors and get black. These colors mixed can make a quality of energy.
Colors are combined for a visual appeal, but they are also combined to create a white, which is the most useful (energy wise & considering visual too). This aspect of light is highly researched right now, with about 1 billion dollars going to the research (as of 2015).
Think of the LED RGB and RQE graphs above
We have some idea of the energies used most efficient in the role of photosynthesis.
What all this research is going to, is if we can figure out what combinations of energies are most efficient in photosynthesis, we can create a more effective white light (best for appearance too).
Using specific energies by them self have been proved to be most useful for when an intense amount of energy is needed (blue). Research still has shown there are draw backs (on growth and visually), when using these colors exclusively. This is why a full body spectrum (full body white) is important, along with understanding more intense energy (which we will go into even more).
More info on:
How we measure light energy- What is a Photon
The Sun and Plant Growth- artificial light and plant growth
RQE Vs. PAS
PUR Vs. PAR
Ways to Measure Output Energy (High-Lower Usefulness)
Photosynthetic Active Radiation (PAR)-“Photosynthetic Photon Flux (PPF)” & “Relative quantum efficiency (RQE)/Yield Photon Flux (YPF)” Quantum Meters:
By today’s science, we measure energy (light) on spectrum frequency call Electromagnetic Radation (how we get most charts used in this review). With more intense energy waves from the Ultraviolet side and less intense on Infrared side.
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The “electromagnetic spectrum” of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object.
Electromagnetic Spectrum- Wiki
The best matrix for measuring useable light energy is Photosynthetic Active Radiation (PAR). While this is one of the best matrix for a standard aquarium keeper, it’s still a method, which miss a couple important aspects for plant photosynthesis when considering artificial energy usefulness. This is how we have two understandings of PAR and one can be considered useful.
The best way to describe these measurements is to let the experts do the explaining:
Photosynthetic Photon Flux (PPF)- (µE m-2 s-1 above)
“The most common method of measuring PAR gives equal value to all photons with wavelengths between 400 and 700 nm and is referred to as the photosynthetic photon flux (PPF)…”(ideal quantum response line).
However, photosynthesis is driven by photons with wavelengths below 400 nm and above 700 nm, and photons of different wavelengths induce unequal amounts of photosynthesis…
*Graph showing both PPF and YPF PAR readings
Yield Photon Flux (YPF)-
“Photosynthesis is fundamentally driven by photon flux rather than energy flux, but not all absorbed photons yield equal amounts of photosynthesis. Thus, two measures of photosynthetically active radiation have emerged: photosynthetic photon flux (PPF), which values all photons from 400 to 700 nm equally, and yield photon flux (YPF), which weights photons in the range from 360 to 760 nm according to plant photosynthetic response…” (Li-COR Senor Line).
“For these reasons, an accurate measurement of PAR should follow the relative quantum efficiency (RQE) curve originally developed by McCree (1972), which weights the photosynthetic value of all photons with wavelengths from 360 to 760 nm. A sensor that responds according to this curve measures yield photon flux (YPF)…”
“The Stark-Einstein Law states that one absorbed photon excites one electron regardless of the photon’s energy between 400 and 700 nm; this law is the basis for weighting photons equally. However, although >90% of blue photons are absorbed, 20% of these photons are absorbed by inactive pigments; their energy is not transferred to energy-collecting pigments (reaction centers) and is lost as heat and fluorescence. This loss means that the quantum yield of absorbed blue photons is typically 20% less than the quantum yield of absorbed red photons. Species differ in their proportion of inactive pigments…”
“genetic and environmental influences on quantum yield…”
“In spite of these genetic and environmental influences on quantum yield, McCree (1972) found that the spectral quantum yield of healthy, green leaves of 22 crop plant species differed by less than ±5%, so he defined an average RQE curve. Inada (1976) obtained a second set of comprehensive quantum yield data (from 33 species) and confirmed McCree’s (1972a) measurements.”
“Quantum sensors designed to measure YPF or PPF are commercially available. Both types use multiple-spectral filters in front of a broad-spectrum radiation detector…but neither type matches its desired curve ”
Accuracy of Quantum Sensors Measuring Yield Photon Flux and Photosynthetic Photon Flux
PAR Quantum Meters (Apogee) available to most hobbyist (budget based) and measure Photosynthetic Photon Flux (PPF), which values all photons from 400 to 700 nm equally, which is the first mismeasure of weighted photons in the range from 360 to 760 nm according to plant photosynthetic response Yield Photon Flux (YPF). PAR Li-COR Quantum Meters are available to hobbyist, but more industrially uses to measure YPF. These meters are more expensive.
Now we can combine what we know about energy measurements, and know about how much input energy goes into how much output energy.
Spectrum of a 6500K AquaRay GroBeam, using ALL Cree 6500K XB-D emitters
All spectrums found on a fixture box will be a rough estimate of the overall spectral make-up of all combined emitters. Some fixtures use all the same emitter, so this spectrum is the energy emitted from the one emitter.
MORE useful information would to understand each emitter in the fixture and each output spectral frequencies it produces. If considering each emitter, wattage of each emitter can be considered for total output of the fixture. (More info in the Combined Spectrum Section)
-The example above is of a 6500K (more about Kelivn below) aquarium plant fixture, which happens to use all the same 6500K emitters. So, the spectrum of the emitter will be the same as the overall output of the fixture.
Consider the spectrum of the Sun, shown earlier in the review
***See how their different and what could be considered as useful. We know all energy is useable, so we want to provide it to our plants. Allow the plant to chose what it wants to use. With a limit input energy (Set number of photons), we have to consider our maximum useful output, by using what we know about energy frequencies (blue is most efficient).
So what do we do with limit (watt/photon) inputs, we focus more (photon) in more efficent energies (remember the Nobel Prize, blue energy talk?), which is really what has allowed us to take huge steps in technology to get the most efficent lighting (T12-T2- now to LED). WHILE trying to provide all energy, which plants find useful in someway.***
So, we add our higher energy blue. Focus more Photons in the higher frequency.
AND, we try to get our FULL BODY spectrum, similar to what we know the Sun provides.
Now, this can be done in a million different ways, including, just using one frequency emitter (one color) only, using a white emitter combined frequencies, OR using separate frequency (color) emitters and adding them all together to get the overall output frequency energy.
Different emitters will have more energy focused in different spectrum frequencies, either blue, more maybe in the middle of PAR.
By taking a look at the spectrum of each emitter, we can get a estimate of how much input energy is going to different output frequencies desired.
Remember the Action Spectrum of Photosynthesis.
Typical PAR action spectrum, shown beside absorption spectra for chlorophyll-A, chlorophyll-B, and carotenoids
This too is important to understand where the output spectrum of a fixture (really each emitter), is going to feeding the important processes of photosynthesis. While all frequencies are used (PAR), these frequencies have shown to trigger different rates and mass of growth.
A lot of study goes into frequencies and combinations of frequencies to determine rate of rate and mass size. Understanding these actions, helps us make the most efficant light (energy) for our desired outcome.
By adding the blue, we get more intense output energy to the plant, while also providing the useful frequency energy needed in the MAJOR process of photosynthesis.
Why not just provide the same spectrum as the Sun?
When considering a limit energy supply like an artificial light, we cannot just provide the same spectrum as the Sun, as we would actually get less efficant growth, considering what we know about frequencies and PAS/PAR. By using what we know (ultimately adding more blue energy to our spectrum), we are able to use less input energy and get more useful output energy. If we used the Sun spectrum as the only frequencies we provide, we would get growth, even with more input energy, considering we have a limit energy supply.
If we didn’t to worry about input energy, providing more energy (more than the plant can use) in all frequencies would be best (Sun), allowing whatever photosynthetic creature to use whatever it wanted, whenever it wanted.
So, in a general sense, having high amount of blue energy and a full body spectrum is best overall usefulness, cause it give us the intensity of the blue and the full body, which is needed for the plant or coral to use, whatever it needs. When it needs it… (different plants need different frequencies in different conditions and environments.
Spectrum Section- Emitter Combination
Kelvin, Color Temperature & Spectrum:
Lights will have Kelvin rating, which is a unit of measure for temperature and is commonly used to describe the type of light one can expect to see from a light fixture and is loosely connected to the light energy in Nanometers.
Simply put Kelvin Temperature is basically a measure of color hue and different hues “colors” have been shown to grow plants best for mass or fruit production…etc Generically speaking, cause color does not determine growth.
Kelvin is the color a black body radiator (such as the Sun), is when it heats up. The sun highest in the sky, plus blue sky equal 6500 Kelivn. The Sun lower in the sky and later in the seasons, will be warmer at say 3000K. Stars which are hotter or even fire, will have a blue appearance, which we might rate at a 12,000K blue Kelivn.
The color temperature (what we see) of a light source is the temperature (Kelvin) of an ideal black-body radiator that radiates light of comparable hue to that of the light source. Color temperature is a characteristic of visible light.
The CIE 1931 x,y chromaticity space, also showing the chromaticities of black-body light sources of various temperatures (Planckian locus), and lines of constant correlated color temperature.
Color Temperature- Wiki
In physics and color science, the Planckian locus or black body locus is the path or locus that the color of an incandescent black body would take in a particular chromaticity space as the blackbody temperature changes. It goes from deep red at low temperatures through orange, yellowish white, white, and finally bluish white at very high temperatures.
Planckian Locus- Wiki
White light can been seen these color temperature charts.
Spectrum and PAR
Here’s a graph typically used for an aquarium light. Along with what specific light output, we can see intensity light input as far as photosynthetic active radiation effectiveness. Blue is 100% effective [More in detail about this below]. We can see the physical amount of combinations of energy frequencies to make a certain visual/non visual output.
The study of measuring absorbed radiation is Absorption Spectroscopy, which then then apply to plants and corals. More information:
Absorption Spectroscopy- Wiki
Applying to aquariums
6500K white has been shown to have the highest growing power* for terrestrial plants. There’s something about this combinations of light, which will gain the most mass in natural outdoor photosynthesis (plants grow more mass in Summer months where the Sun is intense). 6500K is when the Sun is most intense, providing the highest combination of frequencies of usable growing radiation.
*This is very generic and is a blanket statement for plants in general. What’s best for a plant can vary considerably considering environment and makeup of the plant and what it needs at a given time. Think of seasons and how plants know when to create fruit.
Kelivn is like paint where all paint make black, all hues of color make white.
Think of how 1+9=10 as well as 5+5=10, as there are many ways to reach a Kelvin Temperature (like mixing paint) and not all are going to be equal.
You can have a straight 6500K white, but taking say a warm white of 3500K plus a 50K, which is close to 6500K. These two color combinations cannot be the same, even though they both have a 6500K rating.
Again, I can have a 6500K primary made of blue 10,000K and some color from the red end of the spectrum and this will be much different than mostly warm white colors and a high K rated combination to make 6500K. These Kelvin ratings are the same, but the quantity and the quality can be considerably different. This will even be different than the common warm/cool white combination, which also has a 6500K rating.
In this case, the 6500K with more blue will have more usable/quality energy for photosynthesis, based on what we know about the PAR/Action/Absorbent Spectrum and the LED study above.
We are also finding that with along with just blue, it’s a combination of color, which will produce the most mass on a plant. We could say, lets just grow our plants under blue light, but this has shown negative impacts on plants, which is why full spectrum are recommended, at least for plant growth.
Green light: Is it important for plant growth?
How much of these combinations is the billion dollar question. This is the term I would like to coin as Synergy. The Synergy of output frequencies we get from a fixture, is what can become more useful in different applications.
Similar can be explained for photon demanding reef marine aquariums, which require energy to deliver photons in the near ultraviolet light range.
Using this same example and assuming 1 and 9 are nanometer wave lengths, which are desirable, and 5 is not, the light using the 5’s are poor even though they achieve the same Kelvin rating!
The latest technology LED lights are very fine tuned in exacting wavelengths/nanometer energy outputs found within the best Kelvin Color temperatures.
Achieving the correct wavelengths in the correct amounts has been the challenge and is why a simple LED flashlight has about as much in common to an advanced aquarium LED as paper glider to a Boeing 777 airplane. Try hanging several LED flashlights to grow your delicate coral or plants, it will not work the best!.
Another popular trend is LED fixtures that allow the user to control color temperatures. These gimmicky and misleading RGB and Capacitive Touch features are completely useless, however these are popular “bells and whistles” that unfortunately many without a full understanding of lighting PUR fall for.
Controlling your RGB (Red, Green, Blue) of your light has little bearing on obtaining the exacting nanometer spikes necessary for photosynthetic life.
In fact the best emitters are designed to run at a specific color whether it is a XT-E cool white or XT-E 10,000K, and attempting to alter the color simply degrades the PUR.
Other RGB features utilize green, red, yellow, and other color emitters, but again, by attempting to dial in say a 6500K or 18000K Kelvin temperature, all you are doing is wasting copious amounts of energy in light spectrums that provide little or NO useful PUR for photosynthetic life!
The bottom line is there is no benefit from the RGB feature and in fact, they’re stressful/harmful to coral or can encourage algae growth with freshwater LEDs with this gimmicky feature (this feature is my main complaint with the otherwise good Pacific Sun LED). If maintenance of an aquarium is off, the colors from these RGB, while be the first aspect to cause algae in an aquarium.
- Watts Per Gallon?
This is basically an “out of date” equation when used to cross compare lighting types, however we still can use it when comparing apples to apples.
In other words the newest generation LED emitters such as the similar patented CREE emitters would only require about .6 watt per gallon for high light Planted Aquariums and .8 watt per gallon for most Reef Tanks (under 24 inches). About .2 watt per gallon can be added to either (FW or Reef) for even more light or more depth over 24 inches.
However this does not apply to the many lower end LEDs now flooding the market such as the “New Fluval LED Lights” which provide little specifications other than CRI, which is not a parameter that should be used to rate any aquarium lights. These would be more like 1.5-2 watts.
Citation: Aquarium Lighting; CRI
Circuitry & Current Reduction Vs. Pulse Width Modulation:
What is missed by many “lesser” knock off LEDs, is the drivers/circuitry used to power each emitter. Like daisy chaining Christmas lights together, one simply daisy chains an LED emitter without changing voltage to each emitter in the chain. It’s this circuitry, which separates 80% of LED fixtures from the 20%, which have the proper circuitry and thus are more expensive drivers to maintain exacting voltages between each emitter.
Emitters are meant to be ran at a certain voltage to maintain their spectral quality.
Without the proper divers, if dimmed the emitters will have an increase of current applied to them, which is stress on the emitter. Over time, especially when moisture is involved, this stress can lead to degradation of the emitter and it will burn out. With even one emitter burnt out, this can cause shifting of the lighting spectrum. This is how it’s explained by a electric engineer.
The shift of a LED lighting spectrum can be seen by using an incandescent bulb as an example.
This applies to both LEDs intended for Reef and Planted aquariums and by theory, can be different depending on how many emitters are chained together. Say 10 versus 300.
Here is a helpful video I recently found that visually demonstrates color shift in dimming:
Incandescent dimming- cooler blue to warmer yellow color.
This concept applies to controllers, which dim and brighten an LED. A controller best maintains the voltage output via pulse width modulation [PWM]. This applies to fixtures, which do have a dimmable driver in the unit and allows it to use this controllers using PWM. Only a few brands offer this technology and can also be incorporate in DIY set-ups easily and at a decent price ($8).
Fixtures with PWM divers, cannot be dimmed with standard 0-10v dimmers, such as Apex.
PWM is important as it’s effectively turning the LEDs on and off very quickly (faster than the eye can see) so there’s no change to the voltage/current output as opposed to using 0-10v linear or analog reduction (aka current reduction)/manual intensity controls used by many brands of LEDs.
This technology also will lower the watts to be used in LED fixtures proportionate to the voltage used, which will in the end save in operation costs. 10V dimming will always used 10 volts, where PWM is proportionate, so dimming at 5 volts will use 5 volts of energy.
“The main advantage of PWM is that power loss in the switching devices is very low. When a switch is off there is practically no current, and when it is on, there is almost no voltage drop across the switch. Power loss, being the product of voltage and current, is thus in both cases close to zero. PWM also works well with digital controls, which, because of their on/off nature, can easily set the needed duty cycle.”
YouTube Video Circuit Skills: PWM [Pulse Width Modulation]
HOWEVER this technology is not cheap! Up front. Compared to the lesser brands on the market, the cost might be $100-$200 more. But, the idea is to save more power for savings down the road. Also to preserve the life of the LEDs, which is also applied to savings of not having the replacement emitters/fixtures.
It also has been noted, PWM makes a pitch noise while dimming. Looking for some information from the manufacturer about this claim, TMC does note that the sound is present, but they also state that in many test with many users, the sound can hardly be noticed. 90% claimed there was no issue with the sound. The sound is proportionate to the ramp, so at less %, the sound is lighter and 99% would be the loudest. Even still at 99%, the sound is hard to hear and is something that easily blends into the natural sounds of the aquarium.
Unfortunately, the vast majority of LED fixtures utilize 0-10v current reduction (manual controlled rheostat), which can alter the light spectrum and also produces much more excess heat due to how “current reduction” (Voltage/Current relationship) works. As well, while some Chinese LEDs are now being supplied with PWM, these utilize a basic form similar to how an electronic DC to AC Inverter can use square wave, modified sine wave, or pure since wave; with pure sine wave being best and most efficient and square wave being poor and inefficient.
This is also why so many high wattage output LED fixtures require a fan. As the heat created by the amount of emitters (including excessive heat from dimming) on the heat sink is more than the sink can handle. This includes both low end LEDs or even many of the “better” more popular brands.
What’s also worthy to note is this wasted heat then requires a cooling fan, which represents more wasted energy, which could have gone into lighting output your aquarium. Wasted energy converts to heat… This is why ANY aquarium LED utilizing “linear or analog reduction”, which is the vast majority, requires a higher wattage and more emitters to provide the same useful amount of light energy/PUR so as to provide the same results as an aquarium LED that utilizes PWM and drivers!!! Lesser fixtures can waste up to 50% of it’s energy used in a combination of extra parts (fans) requiring energy, wasted heat, and poor spectral quaility/quantity.
With Current Reduction, you are wasting considerably more energy not just in wasted heat, but also when lights are dimmed. If you dim your lights at night, you are still using considerably more watts of electricity than with PWM.
PWM uses only the amount of energy required to drive the emitters at the voltage required. This cannot be said for a simple intensity control (even little digital screens intensity controls)!
So the long term energy costs with any LED, which uses extra parts, poor circuitry/current reduction (MOST), is going to be considerably higher, often paying for the PWM tech. in most cases under a year!!
Lack of full PWM, also can cause much quicker degradation of the circuitry. The result is often a much shorter LED fixture lifespan (not the 50,000 hrs emitters are rated for), which is why so many, if not most LED makers only warranty their product for 3 years or often much less. Often less… (heat damage from fans plays a major roll in shortening of the life of an LED fixture).
This is where it’s rather disingenuous [in my opinion] to advertise a 5 year lifespan while only warranting a product for a year. Most times, the fan will even stop working well before the life span of the emitters, making the advertised lifespan useless.
Sum it up:
While Current Reduction and PWM both have their own pros and cons, from the aspect of a quality LED fixture, the lack of PWM (& use of Current Reduction) along with daisy chaining of circuitry is just one MAJOR reason NOT to consider ANY LED, which uses dozens of emitters to provide the amount of desired light lumens.
Yet, most the LED fixtures use dozens of emitters daisy-chained together, which is a shotgun approach (& more wattage/wasted energy) to provide required high output lighting.
In fact, even an emitter from a “newer” bin such as Cree XTE, which is simply daisy chained together, will lose emitter spectral quality too if they are just used in current reduction or manually dimmed. Versus the same Cree emitter, which has the correct constant current drivers to tie each and every emitter together.
Examples of these current reduction fixtures include the Blue Moon, TaoTronics, SkyLED, Marine Skkye, Fluval, Ocean Revive, Build My LED among MANY others.
- Emitter Combinations Vs. Specimen Placement
Specimen placement is a major determining factor for which emitters to use (in nanometer/Kelvin output), in fact this is more important than the actual tank depth if for example all the high light requiring specimens are placed at 12 inches or higher in a 30 inch deep tank.
As a generalization, the use of more blue and/or higher Kelvin daylight is necessary for specimens, which are deeper in the water column (such as 14000K daylight for depths past 12 inches). Another consideration is whether the emitter is wide angle or more focused, as this can determine which emitter combination is best based on specimen placement.
For instance a Maxima Clam that is placed on the bottom of a 24 inch deep tank will likely do best with more Reef Blue emitters (50,000K @ 465-485nm) in the emitter mix, or even supplemental 20,000K Metal Halide.
Or better, I would suggest placing the Maxima Clams on shelves higher up on your “live rock” reef. (To keep your Clam off the bottom away from bristle worms, etc. as well as provide better lighting to your clams) Depending upon how far under the surface you place these and other photosynthetically sensitive inhabitants will allow for more wide angle LEDs such as the 1500 Ultima Ocean Blue.
Coral such as an Acropora coral placed on your tank “reef” at 6 inches under the surface may do well with lower daylight emitters, Which still have a high output and light spread.
With freshwater plants, this also holds true to some degree, so if a tank is well terraced, standard 6500 daylight emitters should be fine for most plants up to 20 inches, however adding higher Kelvin daylight, such as the Marine White 14000K might be suggested for tanks deeper than 24 inches.
LED Light Comparisons/Tests from 2008
For this test, full spectrum LED Grow Lights similar, but with a lower output to the newest version of the TMC GroBeam 6500K Daylight or 6500K TMC Mini 400 were used.
In this test, the LED Lights were PROVEN to substantially surpass Metal Halide Lights in growth. While this test is now somewhat dated, it is this test, which convinced the industry, that LEDs have “now finally arrived” as a useful light for planted freshwater and reef saltwater aquariums.
The raw data based on this study with plants that a 12 Watt LED can at least replace a 100 watt MH of equal Kelvin ratings in aquarium applications. High output 30 Watt LED should easily replace one 175-250 Watt Metal Halide of similar rating for marine applications up to 24-30 inches in water depth.
See this link for more: Premium Aquarium LED Lights
Further LED Fixture Emitter Information, Myths:
- Correct Wave Lengths:
As earlier noted, it is important to understand that not all emitters are equal, even the Cree or other binned emitters sold commonly for other applications are only as good as their correct wavelength output.
This is where there’s much misunderstanding as to emitter abilities based on emails friends and I in the aquarium hobby/industry have received.
Many think that high end patented emitters are equal to emitters sold for DIY projects or the many LED fixtures readily available in stores or the Internet which is simply 100% incorrect!
In another example, the nanometer range in the licensed-patented “emitter bins” used in the CRee XR-E for their blue are very specific, utilizing the maximum PAR range of 465-485nm found in the blue spectrum (400-500nm), unlike other lights and even other LEDs which either have multiple spikes.
Others such as the CRee XT-E peak at 420nm.
By peaking at these important spikes, maximum PAR needed by zooxanthellae photopigments in many corals is achieved.
Reference: Useful Light Energy for Photosynthetic Life
For instance, Cree Emitters used by Tropic Marine Center AquaRay/AquaBeam should not be confused with “off the shelf” Cree emitters sold for other lighting applications, as these do not produce the optimum PAS [Photosynthetic Action Spectrum] of Light required for delicate marine reef and freshwater inhabitants and plants. There are emitters that are designed specially for plant and reef use.
Assuming a Cree emitter is used, as noted elsewhere even within specific bins, many are updated regularly and then sold under exclusive contract.
Those who use the logic as I read on a forum post about wattage such as this: “maybe a nice fixture, but its way to small and you would need 12 of them” [30 watt TMC Reef White] to light my 120g” totally misses the PAS high output concept of a modern LED fixture and is still using the logic that is similar to placing twelve 40 watt cool white T12 fluorescent tubes over a his aquarium.
The fact is, he is 100% INCORRECT and as per light energy as only 4 of these lights would be required for this size tank which has easily been proven both in application and via the science of PAS-PUR, PWM, and heat as wasted energy!
Unfortunately many still refuse to either read or do their homework when it comes to “high end” LED fixtures.
(The Marine Aquarium to the above/left is pictured with 2012 TMC Reef White 1000 tiles & 500 Strips)
Be careful of many albeit capable LEDs now flooding the market that appeal to consumers with “bells & whistles” that while certainly adequate for reef use, fall short of being the best based on the known facts of proprietary emitter bins (as well as practical use).
Also be careful of over hyped LEDs, with high PAR values, which are not required, which will require a dimmer, or there will be serious issues to the plants to corals.
The EcoTech Radion & Aqua Illumination are awesome LEDs that are nicely made and presented, notwithstanding these are also good examples where lighting facts are covered by “flash” and good marketing in my opinion.
The bottom line is while their proprietary 40 and 70 degree lenses and feature rich controllers may be useful, these do not make up for the basics of PUR necessary for marine life along with wasted energy as heat!!
Again, this is NOT to say the EcoTech and Aqua Illuminations are not Reef capable, as use by many reef keepers proves these are capable, only that these LED Lights require a higher wattage input to product the same amount of useful light energy as those using proprietary/patented emitters, NO green or amber emitters (or other useless PAS-PUR emitters), and PWM technology!
PUR and more specifically PAS and excess heat produced equals wasted energy are FACTS of science. As well patents are a part of business, so naysayers can argue and make personal attacks all they want, but these are still facts!
Please reference this article for further information:
PAS-PUR vs PAR, Wave Lengths in Aquarium Lighting
- DIY LED Fixtures:
This brings me to DIY LED fixtures, where I will be brief and point out, this may well be a worth while endeavor (if only for the enjoyment of building your own equipment).
Many have had reasonable success with over the counter CRee emitters as well as Bridgelux emitters.
Even the over the counter CRee emitters are still more capable than the Bridgelux, however with a shotgun approach of Bridgelux emitters many have still successfully kept reef aquariums with these DIY Bridgelux LED emitters [resulting though in much more electrical usage, which defeats the purpose of using LEDs].
Please note all that has been stated here as per emitters and realize that to achieve good results you will need good drivers/ballasts to power the emitters (many prefer magnetic even though they run hotter and use more energy), and as per the emitters themselves you need to follow more of a shotgun approach, since the best emitters are not sold over the counter.
Think of it this way– if you as a automotive ignition system seller have developed (at considerable cost) a new automotive ignition system that increases fuel mileage by 50%, you would want to sell this at the highest possible price with the most up front money to recover development costs.
The bottom line is a successful DIY LED reef light is a reasonable goal, but you WILL use vastly more energy for the same results when you compare DIY Bridgelux LED fixture to a patented emitter LED fixture.
You will also need a strong understanding in wire, lighting, and maintenance. Of course, there will be a lack of a manufactures warranty as well, so repairs are done by the fixture owner.
I also highly suggest adding PWM dimmable drivers for DIY, which is actually a decent price for DIY for the benefits it has. These drivers will run under $10 per channel. It’s recommended to be able to dim these LEDs, starting slow and working up to their tanks lighting needs.
Basic Mounting Suggestion
Each LED should come with at least one form of mounting. Slide out rails, suspension kits, and in hood mounts are most common,
DIY options are east and work for most fixtures.
In fact a DIY rack such as the one featured in this picture does not take much DIY ability at all and easily supports most LED Fixtures.
Depending on how much PAR is being used and even lens used on the fixture, will determine how high the LED need to be mounted.
See this related Aquarium Article Digest Post for further installation options/ideas:
Aquarium LED Light Installation Options
As well I strongly suggest reading this section: Important LED Ventilation
T5 to LED Comparison
*(2) 18 Watt T-5 Dual Fixture = $60
*(2) 18 Watt T-5 Bulb = $30
(it takes two T5 to equal one AquaBeam 600 12 watt in actual useful light energy)
*Startup cost for Fixture and bulb = $90
*Average yearly electrical cost = $15.77
*Yearly Bulb replacement cost = $30
Total T5 cost for 5 years = $318.85
* TMC Led Fixture = $150
*Startup cost for LED = $150
*Average yearly electrical cost = $5.26
Proper High End Electronic LED Venting, Moisture Prevention
Please read the above article section about the importance proper care and mountain of your LED Fixture Investment
In my conversations with aquarium professionals, as with ANY lighting or change of lighting; results should be seen WITHIN 6 weeks, whether positive or negative!
Regardless of the lighting type, if the corals or freshwater plants take a turn for the worse in say 3 months after a lighting change, likely there are other lighting parameter issues at play!
Both corals or plants will need time to adjust to their new lighting. Depending if the adjustment is to higher or lower light, both will “melt” back and regrow to the new lighting. It’s recommended to start slowly and work up.
Back to LEDs in particular;
The flaws of LED aquarium lights are quickly disappearing and based on the energy savings in electricity in wattage of the lights (as compared to MH) as well as electricity use for air conditioning or the cost of a chiller often necessitated by larger Metal Halides. I should also note that LED light technology is growing by “leaps and bounds” and many of the bugs including price are currently being improved upon.
LED Lights such as the The AquaRay LEDs, Orpek and a small handful of other LEDs are constantly improving their PAR and more importantly PAS by utilizing the latest [often expensive] patents or high in house development costs (or both)
Unfortunately, many popular LEDs that would be considered “good” as recently as 2010 such as the Current Power Brite LED light strip are slowly falling further back
As an example, the “Current” is more of a supplemental LED with an output that is about ¼ that of the best LED Strips.
As already noted earlier in this article, many “new” LED fixtures rely more on slick packaging and cool features rather than the essentials of reef or planted aquarium lighting: “Useful Light Energy”, and sadly this has fooled many forum readers from the feedback I have received.
LED Light systems are easily complimented with T2 fixtures for smaller applications or possibly the high in PAR for large tank applications (the SHO are a bit more DIY in applications, but if handy, they are often worth the extra time, especially for heavily planted freshwater aquariums).
The picture to the above/left is a planted freshwater aquarium with 4 GroBeam LEDs and 4 6400K T2 lights (click to enlarge)
Another less known example are the small tiles useful for larger tank supplementation or Nano reef or planted aquariums.
The TMC Mini 500 & 400 LED are both designed for small Nano Reef Tanks under 15-20 gallons or supplementation of larger tiles or fixtures..
The picture to the left displays this light with a “MountaRay” bracket for easy attachment to small tanks.
This Mini 500 LED includes four lensed CRee patented-licensed XP-E 10,000K and one unlensed Blue CRee XP-E (the White LEDs can be switched off for “moonlight” mode).
Similar is the TMC Mini-400 for nano freshwater planted or refugium tanks.
See this review of the 400 (from Aquarist Magazine):
TMC Aquaray Mini LED 400 Aquarium Light Tile Review
See this Product Source for the Mini 400 & 500:
AquaRay LED Lights; Mini 400 & 500
The bottom line is, when you compare an LED aquarium light to the many popular CFLs in terms of lumens per watt, focused lumens, lower wasted light energy, low heat output, energy consumption and long life (50,000 hours vs. 8000 hours), the modern LED is generally a better light.
In long term cost since (as an example) a 12 Watt Aqua Ray GroBeam (natural Daylight) can easily replace a 55 Watt power compact, such as a Helio, when you compare ALL aspects of lighting as presented in this article (approximately 20-25% of LED wattage is required when compared to a typical HO G11 CFL).
When compared to even older T8/T12 aquarium lights, a third generation TMC Aqua Ray requires only 17% (or less) of the wattage for the required light energy of a planted or reef aquarium.
Another thought to add to this summary, I have found the newest generation high end LED Aquarium Lights to be one of the best lighting innovations for Reef or planted freshwater aquariums, however as of the latest update, there is no LED yet that can replace a 400 watt Metal Halide (currently the best I can give a thumbs up in replacing is a 250 Watt MH). An LED that can replace a 400 watt MH may be available in the future.
As a final note, reading reviews about LED Lights from forums or blogs that have not been updated since 2009 is about the same as a review of a 1993 Computer’s capabilities compared to those of a 2010 computer. As well even then, not all emitter bins are the same, and many otherwise nicely constructed LED lights such as the Ecoxotic Stunner are not using the best technology emitter bins (most of these bins are exclusive) and cannot be used in most LEDs for this reason.
For additional information, please see this full Aquarium Lighting Article from which this Digest article has been allowed to quote some information from:
Aquarium Lighting; Facts & Information
Also see this newer article for LED Installation Ideas:
Aquarium LED Light Installation Options
*XLamp XT-E White:
“Cree XLamp XT-E White LEDs are the highest-performance white LEDs available. The XT-E LED delivers twice the lumens-per-dollar of previously available LEDs in the popular XP footprint. By leveraging the popular XP footprint, customers can easily incorporate the XT-E LED into existing XP LED designs to shorten design cycle and improve time to market.”
*XLamp XB-D White:
“Smallest lighting-class LED enables dramatically lower system cost
Designed to enable lower system costs for lighting manufacturers, the XLamp XB-D LED doubles the lumens per dollar of previously available LEDs. Built on Cree’s SC³ Technology™ Platform, the XB-D White LED delivers up to 139 lumens and 136 lumens per watt in cool white (6000 K) or up to 107 lumens and 105 lumens per watt in warm white (3000 K), both at 350 mA and 85°C.
Cree XLamp XB-D color LEDs extend the double lumens-per-dollar performance of the XB package to color LEDs, delivering up to 40% higher maximum light output than XP-E color LEDs. The combination of performance and small size of XB-D color LEDs enable better color mixing and lower system cost.”
Such as this quote with further verification of our comments about the EXCLUSIVE Cree/TMC emitter rights:
“TMC, in tandem with Cree, tailored the newest Cree XR-E diode Kelvin temperature so as not too waste energy in the unneeded spectrum range. And, the TMC tiles do not use cooling fans”
*St Mary’s Marine Biology Experiments
A few Articles within this website I recommend
*A Push for Excellence
*The man behind the study
*And, so it Begins. How to Mount?
*Experiment Update 1
*Sustainable Science Thesis & Abstract Update
*Economic Analysis of Greenhouse Lighting: Light Emitting Diodes vs. High Intensity Discharge Fixtures
[A good read, albeit aimed more at growing terrestrial plants than practical LED application in planted and especially reef aquariums. The comparison between HPS & LEDs misses what corals and even plants that live in water need as per PAS. Practical experience long before LEDs were even available for reef use shows their comparison to be false as noted by another source I cite that also cites this otherwise useful resource].
*Advanced Aquarist; The Best Lamp Is
[I do not totally agree with the methodology and conclusions [rather flawed in that much is left out], but still an educational read]
*Input from several aquarium professionals including: Aquarium Design, and Quality Marine USA (the largest importer of marine fish in North America)
*Red Slime Algae; Cyanobacteria in Aquariums
I should note that if you also have a UV Sterilizer, changing the UV Bulbs every six months can help with Red Slime control along with the more important aspect of good lighting with little of the yellow light bands.
So as to keep this already long article readable; NO Further Comments will be allowed; Thanks for understanding
OTHER USEFUL/INTERESTING WEB SITES:
Excellent professional and experienced information about Reverse Osmosis (RO/DI) systems (A MUST READ!):
Use of RO, DI, Softwater in Aquariums
Recommended source for UV Sterilizers:
Aquarium-Pond UV Sterilizers
Copyright 2016, By Steve Allen