Further Revised 11/25/15
- Emitter History & Construction
- Input Vs. Output
- Water Penetration
- Low-High Tech Requirements
- Specimen Placement
- Emitter Combinations
- Watt per Gallon?
- Circuitry- Driver/Converter
- Current Reduction 0-10V vs. Pulse Width Modulation
- More Information
- Measuring LED Output
- Measuring Output Energy Theory
- LED Cautions
- DIY LED Fixtures
- Basic Mounting Suggestion
- T5 to LED Comparison
- Requirement of energy using fans.
- Daisy chaining of emitters instead of proper drivers.
- Use of 0-10v instead of PWM
- Newer emitters can be driven at higher efficiency, thus requiring lower input energy, for the same or more output energy.
- 9% at 6 inches
- 16% at 12 inches
- 26% at 24 inches
- 33% at 36 inches
- High Output LED lights do not have the heat problems of Metal Halides, use VASTLY less electricity, often last 50,000 hours, and are very compact. Some LEDs do produce a lot of heat too. If the fan fails, the fixture has to be replaced. LED fixtures with fans cannot be expected to last as long as the rating of an emitter, as the fan is not rated to last this long. This makes the LED fixture rating of 50,000 faulty.
- New generation LED emitter technology is able to control exact nanometer spikes/range, which undesirable UV-B can be avoided. Many Metal Halides, often have some below actinic light energy, even if in small amounts this UVB can burn delicate corals.
- Any lighting or change of lighting, results should be seen WITHIN 8 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.
- Photosynthetic Photon Flux (PPF) – µmol m-2 s-1 (Common to the hobby, nonstandard). Amount of photons at a given second
- Yield Photon Flux (YPF) – ueinsteins/sec/m2 (Industrial, more weighted measure, standard). Amount of usefulness from the photons at a given second.
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.
Also note, with the latest revisions to this article, I have added more advanced lighting science information. A full reading should provide the reader a very good understanding of what makes a GREAT LED for a planted or reef aquarium. Even skipping over the more technical sections should still help any reader make a more educated decision.
Aquarium Lighting- Facts & Information
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 computer chips making micro-explosions, emitting photons in frequencies of waves. Some of these waves, we know as light.
High end LED fixtures use complex circuitry to precisely spread electoral voltage over drivers, which control each emitter. LEDs properly driven will give large amounts of precise frequencies and not shift or lose energy, unlike ALL fluorescent lights.
For some LED fixtures, this statement cannot be made, because emitters are not properly driven (ie. Christmas lights, no driver/converters), daisy chained together, in a shotgun approach to output energy.
For aquarium use, the development of LEDs (2007) for both reef and freshwater planted, was trying to get a high amount of energy (carried by photons) into light used in aquarium photosynthesis. Ultimately delivery more usable output energy with less input has been the big advancement for this new technically. Providing the highest PAR combined with an optimum PUR as per application with the least amount of input energy used, we know is important.
[PUR = Photosynthetically Usable Radiation] total useable amount of energy for whatever photosynthetic organism being grown.
While knowing nothing about photosynthesis is required in order to grow plants or corals, it’s nice to be able to read some of the specifics published by light manufactures to understand how effectively we are growing. It does give an idea of the type of color and energy we can expect from our light source.
Further Reading on LED Basics:
Aquarium Lighting; LED Lights
See what a quality low input/high output LED can do for a reef aquarium. Here’s an excellent newer website documenting the marine LED research at Saint Mary’s College of Maryland by Dr. Walter Hatch, showing better growth, spawning, and more compared to high out energy.
St Mary’s Marine Biology Experiments with LED Lighting
Sustainable Reef- Optimal Growth at Low Energy Consumption
At the end of this review, we should be able to understand these light measures of an LED:
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 due to soft and hard corals being able to thrive under the newer exacting high output LED’s. Many harder corals placed in an aquarium would simply waste away.
This is due to exact energy (light) output.
By this time, many planted freshwater applications were already having success with LEDs, such as the 6500K [high energy white] PAR 38 lamps.
[6500K is the rating of the Sun at high noon w/ blue sky. More below]
Not low output 3000K PAR 30 sold at Home Depot as an example.
6500K PAR 38 Plant LEDs
Emitters are driven at different intensities to provide more momentum (speed) of output energy by the electrical driver. Emitters utilize certain compounds, which converts input energy into photon, which travel at different intensities (output energy) known as light delivered to plants and corals.
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 delivers output energy delivered out through a lens of the emitter.
BRIEF OVERVIEW OF LED LIGHTS:
How LEDs Work
A graph later in this article shows blue light being most efficient, followed by red, then blue. The green is 50% less efficient than the red, and a whopping 80% less efficient than the blue.
[Explained more below, please click HERE].
Further Reference, including a further explanation of the LED vs MH Plant experiment pictured above:
Real World Application of RQE, PAR. PUR, PAS, & Photons
Think of the high end LED fixtures… these are computers, which emit frequency wavelength needed for tank inhabitants.
[See Proper LED Ventilation].
They’re name brand emitters, which are known by many people. 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. There’s debates with each companies designs.
Cheaper fixtures will use no name emitters.
Different emitters can have the same appearance rating, but not have the same quality or quantity of output energy to create the overall visual/non visual spectrum [PUR]. Sun daylight white 6500K from Cree is not going be the same makeup/output or visual as a 6500K from Phillips or Bridgelux. There will also be differences in the way they are driven for more or less momentum giving less or more force for delivery. There’s differences in straight 6500K emitters and differences in the overall combination of emitters/color to make an overall specific output energy and visual color rating [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 can be and what should be expected to pay for it. Different emitter companies will have standards [some patented/specific application agreements or licensing] of how they design their frequencies and will also have different color selections.
This link shows how certain emitter manufactures can have licensing programs [kind of like a patent] for specific emitters. These are designed specific for the aquarium LED fixture and cannot be bought as a regular “bin” emitter.
Citation: Cree Licensing Overview
These differences will create different quantity/quality for aquatic photosynthesis [plants, corals, algae].
A good example is the Osram Oslon NP Blue which is the first patented emitter designed to provide full spectrum light, with high energy to reef aquariums.
Source for LED Lights Containing these emitters:
Aquarium LED Lighting with NP Blue Emitters from AAP
Input and Output energy is knowing how much energy is actually going to the delivery of photons to the plants or corals.
For example, if a fixture of 120 watts has 1, 2, or 3 fans, those fans require energy, which is not going to lighting. If the fixture gives off heat, it’s wasted energy, which depending on the heat sink, may require fans to disperse the energy. Fans can be about 4 watts each. Different fixtures can be more or less efficient, wasting more or less energy.
Another example of input versus output energy, is a common household CFL light commonly sold in stares to replace incandescent lights. A 13 watt CFL is rated to have an output of the same amount of energy as a 60 watt incandescent light. This difference in much lower INPUT energy is what we are taking about since the CFL requires almost 80% less input energy, than the incandescent light bulb.
This is all due to how the bulb creates the energy and delivers it.
While not as extreme, we still see this difference in LED fixtures…
Here are some of the factors that can reduce or increase input to output energy efficiency:
In a very general sense, coloration of a photosynthetic creature comes from the source of light least utilized in the process of photosynthesis. What’s not used in this process, is reflected back to us as the color appearance of the creature. Green plants are green, because about 20% of green light is not used in photosynthesis. Red plants can be the same, with more red being reflected back.
Color can artificially be applied to a creature, by over providing the color not used and the excess will be reflected back even more.
Intensity has also shown a role of colorations, with some plants turning red under a more intense light.
To have a green plant more green, more green in a energy spectrum is needed. To have red plants more red, more red in the spectrum is needed and provided in a intense amount helps.
Co2 has shown to play a role in coloration as well. Higher Co2, will have a more vibrant color.
Many “white” LEDs (such as high output 6500K) can provide more than enough of these colors (white is created from all colors mixed together) to provide good color to both green and red plants. Today’s fads want to provide much more, so to have a real pop effect to colors.
Coral coloration comes from the Zooxanthellae algae living in a synergic relationship with the coral. The coral houses the algae, and the Zooxanthellae algae feeds the coral.
Zooxanthellae are brown in appearance, so the color we see are fluorescent and non-fluorescent pigments being reflected back to the eye. This is called various things such as fluorescence, pop, color, etc.
Note, orange/red does nothing for increased coloration in corals other than non-fluorescent pigments, most commonly seen in fish and a few red SPS species. Red is efficient light for coral growth, but it can lead to diminished coloration (browning out).
Many of the LED aquarium lights now available can provide a shimmer effect, which is like the Sun. This was previously only exclusive to Metal Halide lights [even the lower end LEDs can provide this shimmer]. This is due to an intense light source hitting and piercing though the water. The water movement is the shimmer.
That said, many of the lesser end LEDs should ONLY be employed for this cool effect (such as a compliment to T2s or T5s) or very basic fish only tanks.
There has been claims, the shimmer of an LED provides more intense light, which will help growth. There’s no evidence of this claim at this time.
A popular trend of LEDs is allowing a user to control color. These RGB and capacitive touch features are more for personal experience, which are popular for more personal visual appeal and coloration.
Other RGB features utilize green, red, yellow, and other color emitters.
As far as low input/high out or overall construction there’s little benefit for the RGB feature and in fact, they sometimes can be stressful/harmful to all aquatics and can encourage algae growth in certain situations.
The Sun provides high amounts of PAR (1500+ under 1.5 meters of water).
Many variables such as quality of light used, specimen requirements, placement, will determine these values.
Even the hardest plants, carpeting included, have been shown to grow at 20-40 PAR.
For a low tech planted aquarium set-up, lighting PAR can be 20-50 PAR. Mid-High tech would be 50-100 PAR. High-super high tech 100-150 PAR. Super high tech 150+ PAR.
Co2 supplements are recommended for mid-super high tech.
These numbers also don’t determine growth rate. From what we will learn from the Lighting Theory sections, one fixture can have less of a PAR and grow more mass of a plant with less PAR. This is high PAS light energy and PUR lighting.
SPS- High PAR
LPS- Med. PAR
SOFTIES- Low PAR
SPS have been proven to grow under quaility light at 40-60 PAR. They can thrive under high PUR lights. More PAR will be needed with wide spread full spectrum light. 150-1000 PAR
LPS vary wide for PAR requirements.
Softies have been proven to not require more PAR, in fact, growth rate will stay the same with higher PAR.
Here’s the university level study showing this.
Sustainable Reef Science
The light source will determine all of factors for an aquarium, such as co2 or nutrients needs. If algae appears in an aquarium, it could be a result of an unbalanced aquarium, where the light is either to strong or weak for the creatures using the light. Lighting may need to be lowered (decreased) if there’s not enough creatures using it, so algae will use the excess light.
Penetration is to make sure we are getting enough energy down to the plants or corals. This is a reason to have a good amount of more intense energy to allow the energy to travel further. Within reason, because we have to keep in mind what we know about photosynthesis.
Here’s a great picture depicting what happens to light as it’s delivered and spreads out.
Here is the general light spectrum absorption of water:
Lighting in general is nm wave lengths of light such as “near” UVA (400-485nm) do not penetrate glass well.
Direct lighting is best, quartz, plexiglas (acrylic), or polycarbonate to optimize PAR light penetration or in particular where near UVA is important.
Clean tops and lens regularly to prevent build up, which will block light. Even though infrared will penetrate glass better, it will not penetrate dirty glass with algae or hard water deposits on it.
Spectrum blockage Potential:
Glass- 25% will be blocked
Here’s a great video about creating more penetrating energy. The first UV LED.
Blue LEDs and Nobel Prize – Sixty Symbols
The amount of energy delivered to a plant or coral relies a lot on how far the photons being ejected from the fixture, are able to travel. This can also be effected by how much particles or dissolved minerals are in the water.
This means, many times from an LED fixture, the light right under the fixture can be considered high light. As we get further from the fixture in the tank, we get less intensity of light.
With a strip LED fixture, there’s high light under the strip. Square tile fixtures are meant to give a high light all the way from the front to the back of the aquarium. There are also rectangular, spotlight, and point source lighting types.
Here’s an example to show were the most intense delivery of light is coming from this LED strip.
Consider specimen placement. Also know if plants are used, which grow upwards fast, much less light will be in the corners of the tank, due to plants blocking and defusing light.
The focal lens of an emitter will also determine how much light is directed down or spread out, by the angle. Narrower angles are more direct and wider angles are more spread.
There’s general rules of thumb for plant placement in a tank. Usually higher growing plants would want to be used in the back of the tank and on the sides. Lower slower growing plants in the front.
Hardscapes need to be consider and where the plants will be placed around the hardscape. In the planted tank community, they recommend using the Rules of Thirds for specimen placement. Also consider the spread of the lights your using.
As a generalization, the use of more blue and/or higher Kelvin daylight (more output/more delivery) is necessary for specimens, which are deeper in the water column (such as 10-14000K 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.
These considerations are very important for reef aquariums.
For instance a Maxima Clam, which is placed on the bottom of a 24 inch deep tank will likely do best with more intense focused Reef Blue emitters (50,000K @ 465-485nm) in the emitter mix, or even supplemental 20,000K Metal Halide.
Or better, I would be placing the Maxima Clams on shelves higher up on your “live rock” reef. (provide better lighting to your clams, and keep the clam off the bottom away from bristle worms) Depending upon how far under the surface you place these and other photosynthetically sensitive inhabitants will allow for more wide angle LEDs for better overall spread and more energy to get to the specimen.
Coral such as an Acropora placed the reef at 6 inches under the surface may do well with lower daylight emitters, Which still have a some energy output and light spread.
Acropora could also thrive on the bottom of the tank, with enough penetrating energy, a focused force with more momentum.
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 10-14000K might be suggested for tanks deeper than 24 inches.
Fixtures can be made of one energy output or a combination of a few to many. Few emitters can be used, more, to many. The way they are made up and driven are how we come to an overall PUR.
A major determining factor for which output emitters used (in color/PAR output) is in fact getting more energy down to whatever is being grown. For example all the high light requiring specimens placed 30 inch deep tank, I would know I need more energy output for delivery, so I would consider blue in my spectrum.
Best is to use least amount of the spectrum desired and not averaging the total energy over many different spectrums.
Also, where a certain emitter is placed and it’s spread, will have an effect of group, really under the spread of the emitter, not over the entire spread of the tank. Photosynthesis depending on plant, could be different from under a blue emitter to under a warm white emitter. While the overall spectrum is rated for the fixture, that spectrum is not going through the whole spread.
Different whites, say cool to warm whites will be different growths as well.
Emitters can be different wattage’s 1-3 watts. Some fixtures will use less emitters and drive them more for the same light output as using many emitters and driving them less, for the same PAR rating. Correct drivers are needed for, which method used.
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
What is missed by many 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. Different emitters in the same fixture could require different voltages to be run how they were designed.
Emitters can be driven at higher intensities or lower. Many emitter models need to be driven at a lower amperage (mA) say 350mA, so not to short the life of the emitter or risk burning it out from driving it harder. In this model, more emitters are used to achieve higher PAR reading
This is like the difference between T5 and High Output (HO) T5.
Emitters will say they can be driven at higher mA like 1000mA. Calms are made they are not going to last long or will need dimmers (which adds to stress by design on an emitter). In this model, less emitters can be used and get the same PAR reading, because of the extra intense delivery.
Correct drivers are needed for both methods. Also, the amount of emitters used, will determine an effect of long term stress of the emitters, from something like dimming and moisture.
Some patented emitters will be designed to be driven at a higher mA of 700mA and maintain it’s life span. There are also designs to handle differences in variances of amperage, which can happen over time due to longer term moisture exposure.
The mA is the force, momentum, or speed delivery the energy to the plants or corals. The impact of rate of delivery is still unknown, but faster growth has been anecdotally reported.
A fixture will first need drivers, which are able to dim. Some have drivers not for dimming. As voltage comes out of an outlet, it’s AC and needs to be converted to DC, with an power converter.
By design there’s two ways to do this. One with a different method more managing the incoming current. O-10V dimming and PWM. 0-10v is a simple adjustable rheostat adjusting the voltage, which effects the current. PWM is a flashing the volts, without affecting the current.
It’s well know in the electrical engineering community, DC needs to be dimmed with PWM.
With any DC electoral (vs. AC) source, without the proper dimming methods and dimmed, the emitters will have an increase of current applied to them, which will 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.
This concept applies to controllers, which dim and brighten an LED (built-in or Apex). 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 drivers, 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.”
See also this video explaining PWM:
YouTube Video Circuit Skills: PWM [Pulse Width Modulation]
A con to PWM is a high pitched whine can sometimes be noticed at the fixtures, but from use and speaking with others, this is very rare for most persons to even detect this whine and even then the noise of running water and other background noises will wash out this faint whine for most persons who can even hear this, which is only a minority based on tests.
I should also note in an inquiry to TMC, they noted that they have added a capacitor to the LED lights to limit and smooth any spikes and prevent damage to the sensitive electronics. It is this combined with PWM that causes this slight high pitch that only a few persons can hear.
“In order to protect against current spikes that can occur on the mains supply we have made a change to the AquaBeam 600s. A resistor capacitor filter has been added to the lights to limit and smooth any spikes and prevent damage to the sensitive electronics.
The side effect of this is that a tiny high pitched sound is emitted from the capacitor when a PWM signal is applied to the circuit. This means that when the lights are dimmed by our controllers they make this sound. This only happens when the signal is applied – so only when dimming. There is no sound when on 0% or 100% output.
We showed this sound to a number of people and found that most could not hear it until very close to the unit. So the decision was taken that given the noises associated with a standard aquarium (pumps, water movement etc..) this would not be a problem.
This decision so far has proven to be the correct one as we have sold thousands of units like this with hardly any mention of this sound.”
Back to PWM;
PWM 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.
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.
LED fixtures that utilize Linear/Current Reduction instead of PWM may also produce more excess heat too.
This is why an aquarium LED utilizing “linear or analog reduction”, requires a higher input wattage, often with 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 more efficient 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 less than optimum spectral quality/quantity.
With Linear/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 input 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!!
Fixtures will have anywhere between 3 months to 5 year warranties. Some are full replacements or repairs. Some require a certain % of the emitters to have failed. Also consider the Money Back Policy.
Lack of proper circuity can also 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).
Some LEDs 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.
For this reason a fixture should just be expected to be replaced after the warranty period is up. Many fixtures do last past this point, this is just a good starting point for consider replacement costs.
Once the energy is delivered out of the fixture, here are the matrixes we use to measure the light. [Details in Lighting Theory]
This is a measurement of energy used by being absorbed and processed by a plant or coral, which it uses to grow and ultimately thrive [having everything it needs to be healthy]. This measurement is how many photons (light energy) reach a surface at that given moment in time (second). It can also give an idea of the useful growing power based on what we know about photosynthesis.
This is the best matrix for measuring useable energy.
The best way to describe these measurements is to quote experts in the field:
Photosynthetic Active Radiation (PAR) Quantum Meters:
Photosynthetic Photon Flux (PPF)- (µE m-2 s-1)
“The most common method of measuring PAR gives equal value (amount of energy carried in photon) to all photons with wavelengths between 400 and 700 nm and is referred to as the photosynthetic photon flux (PPF)…”.
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… [seen in Mcree RQE]
*Graph showing both PPF and YPF PAR readings
Since we know wavelengths induce unequal amounts of photosynthesis. We come to new understanding of Yield Photon Flux.
“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 PAR have emerged”
Photosynthetic Photon Flux (PPF)– values all photons from 400 to 700 nm equally.
Yield Photon Flux (YPF)– weights photons in the range from 360 to 760 nm according to plant photosynthetic response.
“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)…”
“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”
PAR Quantum Meters available to most hobbyist measure Photosynthetic Photon Flux (PPF).
This is a measurement of energy as wave frequencies. Frequencies, which trigger photosynthesis and photons are a fragment of these frequencies.
This can be the make up of one emitter or the overall rating of all the emitters combined. So we would have to imagine different delivery spectrums depending on the spectrum of each emitter. Added all together.
Quick how we measure energy frequency radiation.
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation (from a source, such as the Sun). 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
For an easy example: Spectrum of Cree 6500K XB-D emitters.
All spectrums found on a box will be a rough estimate of the overall spectral make-up of all combined emitters averaged. Some fixtures use all the same emitter, some combine emitters.
MORE useful information would be to understand each emitter in the fixture If considering each emitter, wattage of each emitter can be considered for total output of the fixture.
[Input vs Output]
Consider the spectrum of the Sun.
***We know all outputs are useable to a plant, so we want to provided them.
Allowing the plant to chose what it wants to use, when it wants. Different amounts/make ups of energy is used for different process such as growth or flower production [We can focus on these spectrums if we know what the plant needs at a given time/season].
With a limited input energy, unlike the Sun, we have to consider our maximum useful delivery output, by using what we know about photosynthesis and energy delivery [blue is more efficient]. Imagine a battery charger. It charges the battery fastest, because there’s much more input.
So, what do we do with limit energy inputs? We focus more input energy a spectrum with the most photosynthesis and delivery effective.
This is really what has allowed us to take huge steps in aquatic technology to get the most efficient lighting (T12-T2. now to LED). WHILE attempting to provide all energy, which plants find useful in someway.
So, we add our more energetic/efficient blue. Photon delivery of more energetic energy [frequencies]. [Which is also a quality of light many plants and corals prefer, more below]
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 narrow energy delivery spectrum emitter (one color) only, OR using a white emitter combined energy delivery, OR using separate delivery spectrums and add them all together to get the overall output frequencies.
Different emitters will have different output delivery spectrums.
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 delivery spectrums desired.
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 efficient growth, considering what we know about photosynthesis and frequencies. If we used the Sun spectrum as the only frequencies we provide (all frequencies), we would get growth and the plant would be healthy, growth would just be limited to the input energy supplied, which is limited in out man-made lamps with limited input energy [unlike the sun]
If we didn’t have to worry about input energy, providing more energy in all frequencies would be best (Sun), allowing whatever photosynthetic creature to use whatever it wanted, whenever it wanted.
This is why some people still prefer Metal Halide lighting.
Considering what we know about Photosynthesis…We could also imagine these spectrums carrying photons:
Typical PAR action spectrum, shown beside absorption spectra for chlorophyll-A, chlorophyll-B, and carotenoids
[more in Lighting Theory]
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 useful frequency energy in nanometers and penetration.
For the longest time 6500K was the standard for plant growth. This is because of the high blue amount, but also has red. Unlike say 8500K, which has more blue, but less red.
Simply put Kelvin temperature is basically a measure of color hue and different hues “colors” have been shown to grow more plant mass or fruit production…etc. Higher Kelvin such a 10-50K will have more of an intense frequency wave, providing more intense waves, which is useful for needing to penetrate water.
Kelvin is not an accurate prediction of the photon effectiveness in nanometer wave length. Just roughly the quantity being provided based on what we know about frequencies.
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 Kelvin. The Sun lower in the sky and later in the seasons, will be warmer at say 3000K. These seasons will have different growing effects on photosynthesis.
The color temperature (what we see) of a light source is the temperature (Kelvin) of an ideal black-body radiator, which 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
These colors will go from white to cooler blue or warmer yellow/red.
This measure was at one time the way we measured energy, when the relationship between heat emitted and energy was being studied. Today’s studies looks at energy in particles [photons] being the ejected light source emitted and not frequency waves emitted by heat.
It comes back to these terms/graphs, where all have an important role in how they work individually and how together synergistically to make up important overall PAR as well as PUR for the application of aquatic plants and reef coral.
Looking at output energy in a theoretical sense, this is an area of more ongoing scientific research, much of it grounded in sound science such as what a photon is and is not, but it is also an area built upon theories too.
This is unlike the “input” side of the equation we addresses earlier in the article, which is much more mechanical in natural and more matter of fact [example: input energy that is expelled as heat is wasted energy, which NEVER makes it to the output energy side of our equation].
- WHAT’S A PHOTON?
A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation. A photon has zero rest mass. It is the force carrier for the electromagnetic force, even when static via virtual photons.
Reference: Wikipedia; Photon
This photon can be at different frequencies, which can be more energetic [higher frequency] and deliver energy more quickly or it can be less energetic [lower frequency] and would deliver energy more slowly.
Please note that the energy carried is still the same.
Frequency Of Photons
Full Spectrum Of The Sun
- PAR, RQE, & PAS
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.
Aquarium Lighting; PAR
Wiki- Photosynthetically Active Radiation
Useful PAR by NM
RQE– All energies used by a plant in the full photosynthesis process (when all energies are provided from a full spectrum, such as the Sun) (RQE Mcree 1972) RQE is how a PAR meter measures.
–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).
Typical PAR action spectrum, shown beside absorption spectra for chlorophyll-A, chlorophyll-B, and carotenoids
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.
This spectrum has been shown to be very efficient for growing a plant, because of the the large role chlorophyll plays in photosynthesis.
Like a battery charger. There’s faster and slower chargers to get a battery to 100%. These nm peaks above have been shown to charge the battery the fastest. This is because the other nm of light are required to be converted into another useable energy, which the blue and red nm are already providing. The blue is also simply providing so more energetic photons. Still red, while in theory does not provide more energetic photons, it’s quality of light creates more growth as well.
These same principles can be applied to human health and how different foods are converted into more useable energy.
This is a major factor to focus on for LED lighting, along with consider the rest of the spectrum for overall health and visual appeal. This creates PUR.
- USEFUL LIGHT ENERGY, PUR, “QUALITY OF LIGHT”
Also known as Photosynthetic Usable Radiation, it can also encompass PAS, but these two parameters are still not one in the same, since there is much more to PUR than the “action spectrum”.
PUR is basically the “quality” of the light photons as per the application. This of course can vary since we know that as an example, and UVC lamp certainly it the correct quality of light if one is attempting to sterilize, but certainly not if one is trying to grow aquatic plants or photosynthetic reef life.
This is a parameter, which still seems to have a lot of misunderstanding, even though it has been around for some time and in fact has been proven in the evolution of aquarium lights over the years.
Here is a quote from Aquarium Lighting:
“Lights as they apply to aquarium use have evolved/changed considerable, since I have been in the hobby and professionally employed in aquarium set-up & design.
We often used “hardware store” warm white T12 fluorescent lights, just in larger “quantities” to make up for the poor “quality” of light, even while planted freshwater could be kept, not so with ANY photosynthetic reef life.
Early on lights such as the Penn Plax “Aquarilux” came out which still was heavier on the “warm” colors, it also had more blue.
Later the Trichromatics and Triton lamps came out with spectrums focusing on the daylight 6500 Kelvin temperature, these made growing planted aquariums easier with less lights to do the same job as earlier lights.
We also had actinic blue lights become available, these mixed with other lights made it possible in the beginning to keep some photosynthetic reef life, although initially these did not thrive. Later T6 & T5 advancements along with Metal Halide lights allowed us to not only keep delicate photosynthetic reef life, but for this life to thrive.
We now have T2, SHO, and LEDs of which the later have lowered considerably the input energy for the quantity of output energy of light that we need for our aquarium keeping applications.”
I use this quote to make a point, which is obvious that we have evolved from use many lights with lower quality of output energy (photons) to fewer lights to perform the same function. This is of course the “quality” of the output energy in photons as well as input energy in joules of energy used to produce this light.
A good example is a Tri-chromatic 40 watt fluorescent lamp will outperform a warm white 40 watt fluorescent lamp for keeping a planted aquarium. Generally more of the warm white lamps would be needed to perform the same task.
Nothing has changed here with the coming of age of LED lights, a warm white or cool white emitter is not gong to have the same quality of light energy as a licensed Cree 6500K Daylight XB-D emitter.
BLUE LIGHT– This has been proven for plant photosynthesis as per PAS, but is also best for penetration. The higher the frequency, the more energetic and the deeper penetration of water and cellular body structure as well.
Of course there is a point where just because it has higher frequency and more penetration does not mean it will always be more useful. Examples could include UVC blue, which penetrates even deeper, but also changes the DNA or mush higher yet would be X-Rays.
From PUR vs PAR; Real World Application of RQE, PAR. PUR, PAS, & Photons:
“Think of how an X-Ray, which is lower waver length and higher energy yet than a blue 420 nm blue photon, penetrates your body. Would a 420nm bluelight work if you need a light that penetrates as an X-Ray does? Of course not as there IS a QUALITY of light/photons based on the application at hand!!!”
PLANT USEFUL ENERGY
Plants can use all spectrums of light for growth and coloration. Blue and red have been shown to be more efficient for the photosynthesis process. Blue high light energy can be used for greater mass growth of a plant. Bluer light such as 10-14K can be used for deeper penetration.
How Do Plants Grow?
Imagine plant photosynthesis as a battery and once the battery is full, the plant can produce an action, which grows the plant. Certain energy can fill this battery quicker, other takes long or are less efficient, but still fills the battery. These energies are highly studied and one example can be seen in the RBG LED study above and RQE.
Plants need all energies for a synergic effective healthy growth.
CORAL USEFUL ENERGY
Corals have adapted to blue light, which the algae under their skin feed on. Blue light is more penetrating, which is needed for deeper water, more salty water, and to penetrate the skeleton on the coral. The algae can also use all light provided in the spectrum for growth and coloration.
Energy Used By Zooanthellaes In Full Photosynthesis Process.
- LIGHT COLORATION
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 [Kelvin/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 in different efficiencies to create a White, which is the most useful (energy wise & considering visual too). This aspect of light is highly researched, with about 1 billion dollars going to the research (as of 2015).
More useful deliveries of energy by them self (Blue & Red) have also been proven very effective for when an limited amount of energy is used, but a higher output is needed. Research has shown there are pros and cons (growth and visually), when using these colors exclusively.
It’s important to note that there are many LEDs now available for the aquarium market that are not intended, or worse, improperly marketed as the primary aquarium lights.
These LEDs often make unaware aquarium keepers or those who do not do their homework to make the false assumption that these LEDs will work for their planted or reef aquariums when in reality, these LEDs are not powerful enough to keep photosensitive aquatic life.
Here are a few examples of LED Fixtures, which are less than reef or planted aquarium capable or simply using a “shotgun approach” so as to be capable:
As an example even E.Shine’s own web site (& documents shared by a friend that was solicited by E.Shine) admits that the older generation 3 watt CREE XR emitters used for their Daylight Aquarium LED Lights vary from 6000~9000K; not the exacting emitters used by TMC AquaRay, Orphek, & a few others!
The picture to the above/left is of an E.Shine LED that is often sold under many brand names such as the Stark LED. This is not the best light one should place over their delicate reef specimens unless multiple panels are used.
Similar is the TaoTronics “Aquarium Coral Reef Tank White/Blue LED Lamp” with non-descript 1 Watt low end LED emitters as well as the somewhat reef capable TaoTronics “New Design LED Aquarium Coral Reef Tank Blue White 2:1 LED Grow Light”.
The TaoTronics LEDs utilize a shotgun approach with less capable unexacting nanometer emitters without adequate drivers to regulate voltage. While these can and do work in reef applications, they partly defeat the reason of having an LED light to save energy as this LED fixture uses considerably MORE energy for the same results.
This compares somewhat to using of a dozen “shop lights” (cool white fluorescent lights) over his planted aquariums to produce the same results one modern GroBeam, T5, or SHO Light will produce.
At least the Taotronics utilizes a decent American emitter (Bridgelux) in a Chinese made fixture, However Finnex is a Chinese made fixture that utilizes the Chinese made Epistar emitter, which is not even to the PUR standards of the Bridgelux or older generation Cree emitters!
What makes these popular is: (1) price, (2) ease of out of the box set up, and (3) availability since these are sold by mass merchandisers.
HOWEVER, it you are looking for a truly planted aquarium capable LED light the Finnex is far from it based on what I have already laid out in this article, not to mention their terrible warranty which is but 1/10th of the best planted aquarium LED light warranty.
It does have good coloration options, which is sought over. Just lacking on growing power.
A really good example of very low quality emitter use in mass is the “SkyLED 36″ Aquarium Light” with 378 LED emitters [sold by Amazon, Truaqua, & a few others]. At 23 watts and 378 emitters, this comes to only .06 watt per low PUR output emitter. Even an online search of pictures/videos shows that this large LED fixture is nothing more than a replacement for a standard 36″ T8 aquarium lamps (cicra 1980) and should certainly never be used for a reef or high light planted aquarium.
Another similar LED fixture with this same shotgun approach is the “Freshwater Bright LED by Beamworks” with .2 watt per LED (as well as too much algae growing blue for a freshwater aquarium)!!
Another yet is the “New Fluval LED” with 312 emitters providing only 25 watts. There is no way to correctly regulate voltage over this many emitters, especially for the price point Hagen offers. Which is why all Hagen and the mass merchandisers selling this LED mention is CRI, not PAR or PUR.
These previously noted LED fixtures have about as much in common to a TMC AquaRay, AI Sol, EcoTech Radion, Pacific Sun, Orphek and other higher end LED as a two AA cell LED flashlight.
An example of a popular LED light system that is not reef or freshwater plant capable is the “Ecoxotic Stunner LED Strips” sold by some supermarket type aquarium and pet stores. The Ecoxotic are well constructed, however the emitter bins used are lacking in many aspects such as lumens per watt, focused lumens, and most importantly, PUR light energy. The PUR is expressed by not being as “fine-tuned” to the exacting nanometer ranges.
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.
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 easy and work for most fixtures. Racks such as the ones featured do not take much DIY ability at all and easily supports most LED Fixtures.
Depending on how much PAR is being delivered 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 are mostly used for coloration now a days. Here’s the cost difference to justify the cost.
(2) 18 Watt T-5 Dual Fixture = $60
(2) 18 Watt T-5 Bulb = $30
*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
(2) Low input/high output 12 watt AquaRay LEDs
*Startup cost for fixture = $150
*Average yearly electrical cost = $5.26
*Total LED cost for 5 years = $176.28
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”
Recommended Replacement UVC Lamps:
High Output UV Replacement Bulbs-Lamps
Recommended source for UV Sterilizers:
Aquarium-Pond UV Sterilizers
Copyright 2015, By Steve Allen