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Post by Carl on Dec 13, 2013 18:45:48 GMT -5
I have once more updated my "PAR versus PUR in LED Aquarium Lighting" article at Aquarium Answers. More examples of how to compare PAR and PUR in simple real world numbers. As well more was added as to the use of current reduction technology to drive and LED fixture and how the excess heat generated byt this common method also equals lower PUR www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by devonjohnsgard on Dec 14, 2013 13:18:15 GMT -5
After seeing what is on the market and what has become popular, this topic is so important.
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Post by Carl on Dec 27, 2013 18:51:35 GMT -5
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Post by Carl on Dec 29, 2014 14:31:45 GMT -5
I have further updated this important article addressing PUR versus PAR. Since the vast majority of LED lights focus on the PAR while ignoring the more science based importance of PUR in achieving the optimum lighting for their aquarium, keeping this article fresh is very important. In this update, I also added a cited news article from CBS news that focuses on how an indoor farm only uses the light spectrum needed, NONE of the wasted spectrum that 95% of aquarium LED lights use that might be more pleasing to our eyes, but is useless for plants, corals, and even just fish only aquariums!! Here is a quote: "In a recent CBS news story, a large "Vertical Farm" in Portage Indiana is using LED lights that are specific to the light energy needed by plants, NOT PAR which so many aquarium keepers seem greatly confused by. This farm uses just the red and blue spectrum, NOT the green and other spectrums that might be pleasing to us and used unfortunately by some of the most popular LED fixtures, but is totally useless to plants and symbiotic zooxanthellae required by corals."Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Feb 5, 2015 19:28:23 GMT -5
I have updated the Aquarium/Pond Answers article about the importance of PUR in your aquarium, especially reef and planted aquariums Here is a snip: "Plants and zooanthellic algae have adapted to certain depths and is why a 6500K light generally works well (or best) for planted freshwater or refugium aquariums under 20-24 inches of water. While zooanthellic algae dependent corals require more 480nm blue and higher kelvin daylight energy such as 9000K, 10,000K, 14,000K, & 20,000K daylight lights as aquarium depths increase (such as 24+ inches of water depth)."A MUST READ Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Mar 20, 2015 18:03:57 GMT -5
I have updated the popular PAR/PUR article on Aquarium Answers again. Here is a snip: "Why would a business use lighting that might look better by containing all PAR light spectrums, including more yellow and green (common with most aquarium LED lights), but then would use more electricity, when using ONLY optimum PUR/wavelength lighting would produce the same or better results for much less electricity costs?
This targeting of optimum wavelength lighting is becoming more and more widespread in industry, it is only a few in the aquarium hobby that are behind the curve and seem to refuse to perform simple internet searches of optimum growing wavelength and PUR."Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Apr 15, 2015 19:07:56 GMT -5
I have further updated the "Aquarium Answers" PUR vs PAR article. Here is a snip: "As noted in PUR or photosynthetic action spectrum, there are variations in plants, aquatic plants, and zooxanthellae, in what these optimum exacting spectrums may be. Often these are influenced by water depths which will filter out red light spectrums more than blue, which is why zooxanthellae will generally require higher "spikes" in the blue spectrums. However what we do know is the generalizations of what these photosynthetic action spectrums are. As simplified example; if one were to use a scale of 1 to 100 to represent PAR, and say one species might need more at 15 while another need more light energy at 20, these still fall within what we know as PUR or the photosynthetic action spectrum. What also know is that any light that has its primary energy at 50 on our simplified scale, we know that this middle energy is much more useless for the vast majority of photosynthetic life intentionally kept in aquariums or grown in vertical farms. "Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Apr 28, 2015 9:20:53 GMT -5
We have further updated the "Aquarium Answers" article about PUR & PAR with an addition to the summary to deal with some ludicrous personal attacks by a salesperson of "Build my LED" "Another argument used to attack the science of PUR/photosynthetic action spectrum is that we can over saturate the plant or coral we are lighting by using targeted wave lengths. This is nothing more than a "Red Herring" argument (being put out by a disrespectful employee/salesperson of a LED seller that should never have employed such a person). The problem with this argument is we are no where near any light saturation with man made lighting. Let's apply common sense logic hear when dealing with such ludicrous arguments; if this were so, why is it we cannot go out in a boat on a reef at night with our most powerful metal halide lights and even come close to lighting to the depths and saturation the sun would provide in this same area during daylight hours??
Come on people, when persons such as this young lady come up with such ludicrous red herring arguments and refuse to do her homework and instead make disrespectful personal attacks on persons such as myself, you need to walk away and avoid those LED companies who employ such persons!"Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.html#summaryCarl
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Post by Carl on Jun 27, 2015 15:22:53 GMT -5
The "PUR/PAS vs PAR in Aquarium Reef/Planted Lighting; LED Wavelengths" article has once been updated in many sections. Here is one such snip of updated information (dealing with RQE): "Be careful about making the assumption that this means plants, especially water plants and even more so photosynthetic corals need yellow and orange light spectrums in any quantities as some online articles imply, as both extensive practical experience by many as well as the science of PAS shows this to simply not be true. Even with Terrestrial plants, we know that blue lights along with even more so reds are what matter for optimal efficient growth, this is demonstrated both practically and factually by the Vertical Farms link I provided earlier where 2/3 of the light is provided by the red spectrums and 1/3 by the blue and NO light from green, yellow or even orange. This is again why (as noted earlier too) why a LED such as the AquaRay GroBeam would not be the best choice for an application such as a vertical farm since it too adds cyan, green, yellow and orange spectrums! We also know from both science and decades of practical experience that without the blue, corals such as acropora will not thrive."Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by angelminx on Jun 29, 2015 2:09:13 GMT -5
Where the health of the tank is concerned (effects of their spectrum/wavelength and lighting duration on plants, etc), what is you opinion on using red lights for night-time viewing, vs. the so-called moonlighting? I was thinking of (eventually) going that route.
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Post by Carl on Jun 29, 2015 9:31:14 GMT -5
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Post by Carl on Sept 10, 2015 16:49:00 GMT -5
I have again updated the "Aquarium/Pond Answers" article about PAR vs PUR/PAS This update includes a new cited .edu source about the use of green light. Snip from the article: "Even within these variations, we do know that certain wave lengths such as green/yellow are generally useless for the photosynthetic life kept by aquarium keepers as research and industrial applications bears out (unless one is purposefully growing cyanobacteria). In fact green light slows plant growth when over 25% but is beneficial under this percentage (Reference #5)."Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Sept 20, 2015 10:57:24 GMT -5
I have updated the "Aquarium/Pond Answers" article about PAR, PUR in Aquarium lighting. In this update, an entire new section was added; "Real World Application of RQE, PAR. PUR, PAS, & Photons" Here is a quote from this new section: "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! Reference #16)
The next study, which is one that made me really start looking into LED lights more in 2007 including in my "Aquarium Lighting" article. This one obviously has a few added variables, most notably the input energy in joules of a Metal Halide is considerably higher with vastly more energy being wasted as heat energy, never going to photons of light. However when you get down to the actual lumens of energy, the Metal Halide is still higher yet the growth rate is still considerably and very measurably lower! Why? The only answer is the photons of light coming from the 6500K LED Grow Light (generic brand) are at a frequency more readily used by this plant, in other words a higher useful energy or PUR.
There are many more real world examples, including those we have already provided such as the average PAR at a Coral Farm that uses sunlight and is still lower PAR than many drive their artificial lights at to maintain a healthy reef aquarium, which obviously screams out that there is more at play than just quantity of photons.
Finally, let me clear something up based on feedback; I am well aware that a photon IS A photon having a very strong science based background (heck, as a child, I rarely read novels, but as my parents can attest to, I read the entire World Book encyclopedia set cover to cover and more than once at that). Just as I know based on radio wave navigation being a pilot as well that a FM radio wave is line of sight while an AM wave bounces, it is basic science that the only difference between one photon of light and another is the frequency and energy level. We know that a blue light is simply a photon with a lower wave length but higher frequency and energy level than a photon of red light, but they are both 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 blue blue light 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!!! Ditto how the visible blue, green, and red spectrum behave, but with much smaller differences in frequency. Bringing this back to photosynthesis, photosynthetic plants and alga respond differently to these varied frequencies of each photon, with water adding to the equation since shorter wave lengths penetrate more readily with a given energy level. This is where we get our useful light energy term from, as do know (as graphically demonstrated above) that certain photo frequencies react differently and thus are likely used differently by photosynthetic life forms. It is noteworthy that while we can certainly make generalizations, we know aquatic life, especially marine life have adapted/evolved to utilize the type of light most common in their environment, which we in turn need to duplicate as best as possible with our still feeble when compared to the sun man-made lights!"Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.html#rqe-par-purCarl
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Post by Carl on Mar 8, 2016 10:50:17 GMT -5
I have updated the "Aquarium/Pond Answers" article "PUR, PAS, PAR in Aquarium Reef/Planted Lighting" Here is a quote from the article: "PUR stands for Photosynthetically Useable Radiation. It is also sometimes simply known as "useful light energy". Another description could be: "Quality of light per application" compared to PAR (Photosynthetically Active Radiation) being the "quantity of light energy" used by photosynthetic life. I think many in the hobby get "hung up" on this term, as it is a "fuzzy term (which I would partly agree), but there are many aspects of science such as we have moved through the discovery of subatomic particles that are based on subatomic behavior, but not as easily measurable such as PAR is. "Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Apr 5, 2016 8:17:37 GMT -5
I have updated the PAR/PUR in Lighting article in "Aquarium/Pond Answers" Here is am excerpt from this article: "So for some aquarium lighting experts to dismiss subjects such as the concept PUR as "theory" I have to respectfully disagree and I would state that this is showing a lack of knowledge or experience of the history of aquarium lighting. We know that many man made white sources will grow plants, how well depending upon the PAR at the level where the plants are located (PPFD) and the efficiency of the often limited light energy we can provide (PUR). However, we also know based on aquarium lighting history that when tri-chromatic, actinic and other "tuned" spectrum light sources were employed, in other words PUR, we did a better job growing these plants and eventually photosynthetic corals, etc. with the same exact input wattages. Example: 40 watt warm white versus a 40 watt Trichromatic or a 40 watt cool white versus a 20 watt trichromatic plus a 20 watt actinic for anemone aquariums."www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Jul 27, 2016 18:04:42 GMT -5
I have further updated the PAR/PUR article in "Aquarium/Pond Answers" Here is an excerpt that expands on the definition of PUR: "As well, we also know based on aquarium lighting history that we simply cannot dismiss the evidence supporting PUR as a fact either. It is unfortunate that many in this hobby will dismiss this term which has been around long before many even were born. The FACTS are, it was and is a useful term in that we knew decades ago that there was a pronounced difference in many fluorescent lights when everything else was equal; from input watts, lumens, length, type, etc and the only difference was the spectral output (PUR)"www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Nov 5, 2016 18:25:00 GMT -5
I* have updated the Aquarium/pond Answers article about PAR & PUR in Aquarium Lighting Here is an excerpt from the article (summary section): "In the end, most modern LED aquarium light fixtures with only a few very low end exceptions can keep the aquatic life they were designed to, whether planted aquariums or reef aquariums. What it really no comes down to is efficiency, and a light with a higher PUR (quality of light) is going be more efficient and require less input energy all other aspects being equal. The interesting fact is most other aspects are NOT equal outside of being able to keep the designated aquatic life as most aquarium LEDs have poor warranties as low as 180 days and even those with better warranties still are only for repair, not full light replacement. Also MOST all do not have the important IP rating for water resistance/proofing (IP67) resulting in a light an electronic lighting device (LED light) that has a poor warranty and less than optimum resistance to water."Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Jan 28, 2017 11:48:00 GMT -5
I have once again updated this popular article on the Aquarium Answers website Here is an excerpt: "In the end, we know that long before the advent of LED lighting, improved PUR would provide more light energy for the same given input energy, which is why along with other efficiencies (including drivers, etc.) the many economy LED lights such as the Finnex require as much as 4-5 times the input wattage as a better higher efficiency LED, often making any savings go out the window."Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl
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Post by Carl on Mar 8, 2017 10:40:04 GMT -5
I have updated the Summary Section of the "Aquarium/Pond Answers" article about aquarium lighting PAR/PUR Here is an excerpt: "Hopefully readers come away after reading this article and its many cited resources with a better understanding of PUR/quality of light, not that I am stating certain LEDs or other lights in particular CANNOT keep photosynthetic life. As well I am NOT stating that if a fixture uses green emitters it is a poor light. While green light has some proven applications in a closed environmentfor more growth when under 24% of overall light spectrum as well as producing a more pleasing overall light when part of the spectrum. However a fixture that is heavier in the green spectrums is going to be less efficient for photosynthetic growth and possibly detrimental when over 25% of the overall spectrum as per cited .edu references. I will also add that one has to look at the preponderance of evidence, both from .edu websites, NOVA, and similar sources as well as practical experiments and use COMMON SENSE that if one theoretical article comes to different conclusions, but the preponderance says otherwise, that we need to go with what in the end the majority of evidence states (not that what a contradictory relative quantum efficiency graph states that does not agree with other evidence and experiments such as cited at Reference #5).
We also need to understand that all these studies using different light spectrums for growth, including green, that these are in closed & controlled environments (which of course are aquariums are closed environments). However in nature it has long been established, including in an episode of NOVA (PBS science series) that green light in the open environment of nature is generally not used. So in the end, when one forces their plants or coral to utilize green light, we can make this analogy: "You ran out of your quality fish food, so instead you feed your fish soda crackers". While not a perfect analogy, it still makes a good point in that you are forcing the specimen whether it be a plant, coral, or fish to survive on less than optimal "nutrition"Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.html#summaryCarl
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Post by Carl on May 16, 2017 13:51:05 GMT -5
I have again updated this article about PUR/PAR in aquarium lighting. Here is an excerpt from the Overview section: "PAR stands for Photosynthetically Active Radiation. This is commonly our starting point for determining whether or not a light fixture is adequate for our needs since it can be relatively objectively measured. Further Reading: Aquarium Lighting; Measuring PAR
Before we go into depth about the meat of this article, we can use the basics of PAR combined with input wattage to get some useful information about the efficiency of an aquarium LED light (or really any aquarium light.
Here are three examples using PAR reading directly under the lights:
* SB Reef Light PRO 32. This is rated at 363 watts input energy with a PAR of approximately 881 (100%) at 400mm of air. This comes to .41 watts of input energy per 1 PAR
* Kessil A150. This is rated at 90 watts input energy with a PAR of approximately 325 (100%) at 400mm of air. This comes to .27 watts of input energy per 1 PAR
* AquaRay Reef White NP 2000. This is rated at 30 watts input energy with a PAR of 380 at 400mm of air. This comes to .08 watts of input energy per 1 PAR
* Finnex Planted 24/7 20 inch model. This is rated at 15 watts input energy with a PAR of 61 at 400mm of air. This comes to .24 watts of input energy per 1 PAR
Obviously this is but a starting point as this article will clearly show in PUR & more, as we have to consider what we are using our lights for from planted freshwater to acropora reef lighting. As per the LED themselves, different optics will also affect readings further out from the the center, which is why all are readings directly under the light. However this certainly is an eye opening starting point as per the old term; "you get what you pay for"."Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.html#overviewCarl
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