Solving the fatal flaw of LEDs - experiment

i have done some digging, and came up empty handed on a meter that reads PUR.

apparently the only way you can calculate PUR is to know the pigment density of the plant your trying to get the measurement on.

Cripple Fight!

cant figure out how to embed it for some reason... its not a youtube vid tho

I am actually thinking about trying out some leds soon, i dont have the space or ventilation to have an HID. This post makes me want to try it even more

+ Subscribed.

I've been following LED's for a long while, just watching various grows and analyzing various specs, but I've got nothing to contribute after everything discussed so far.

I want to subscribe to you personally Hobbes.

kiss-ass

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From Spectrum Technologies - developer of the Jaz

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"Thank you for contacting us regarding your LED application. I am checking with our software and engineering departments if our software currently calculates the PUR watts. In the meantime and if it is not too much to ask, could you send me the mathematical formula to go from PAR to PUR if it exists. Please let me know if we can be of further assistance and I would appreciate that if you reply to send it to my personal email address ."

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The above was a reply to this inquiry:

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"Can the Jazz be set to measure PUR watts as well as PAR watts?

I'm doing experiments with LED and HPS bulbs and light penetration into the plant canopy. I would like to know the PUR watts for both types of lights at different levels of the plant. Using PAR watts will give false PUR readings for the HPS bulbs and lead me in the wrong direction. A quantum light meter would be great other than this.

I believe I'm looking for a spectrometer that measures intensity, but I have virtually no experience with spectrometers/light meters - if you could offer some advice I would appreciate it.

Thanks."

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So a bit of info to get them, and Iamstoned helped again with this:

"the only way you can calculate PUR is to know the pigment density of the plant your trying to get the measurement on."

So, formula for calculating PUR and the pigment density to determine the ... range of the spectrum?

I don't see how there could be a formula to convert PAR to PUR because the mid range (470nm-620nm) could be any value. I don't see how we could differentiate 470-620 from PUR watts in an equation without knowing the exact spectrum of the light, pigmentation, etc.

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I'd be happy with a machine that can swap out two sensors: one for 400nm to 470nm (blue) and a second for 620nm to 740nm (red). 470nm to 620nm is what's going to throw off the experiment. I think finding the right two spectrum specific light intensity sensors that can be swapped out of a machine is what we need. Even if we can only take one side of PAR per reading we can swap out the sensor and do the second side. I'm hoping the Jaz will do both at once.

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from Dr Jorge

"As promised I did some research for your application. Here is what I was able to gather for you and please mind that we have no biologist in our staff to help us with this issue so we consulted some customers that use our spectrometers to measure PAR in the horticultural business and these are their simplified comments several of which you might be able to expand better than me: PUR is actually the PAR(wvl) multiplied by the photo sensitivity of a specific plant. This sensitivity is different for all plants, so it's very hard for us measure this directly. So a common approach will be to measure the PAR and then multiply it with the plant sample specific sensitivity curve.

We think what's important compared to a normal quantum sensor is to have the energy as function of wavelengths. You will need that to get to PUR.



A quantum sensor would only give the total PAR (so integrated over 400-700nm).

As mentioned before our spectrometers and software can measure PAR if radiometrically calibrated, the same spectrometer can help you measure the the photosensitivity by wavelength by reflection measurements (determining the actual absorption characteristic of the sample). I am attaching some papers that talk about the use of our equipment for similar research purposes. I also attached what I considered a nice review ofPAR and other calculations for your review.
Also please check this webpage: http://dspace.lib.ttu.edu/etd/bitstream/handle/2346/ETD-TTU-2009-08-74/BROOME-DISSERTATION.pdf?sequence=5 in this thesis the author has a detailed explanation on how to use our equipment for the measurements.

Please let me know if this information helped you to better determine what equipment you need. I will be glad to help you with a quote or proposal for your application. I wish I had a better idea behind the science involved. On the other hand a quick Google search gave me enough information to be almost certain that our equipment will work for your measurements.


Thanks for your patience and jave a great weekend.


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My reply:

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Thank you Dr Macho. I will break down your post into topics and research each topic this evening.

I would be happy with one light meter that can swap two sensors, or two machines with a sensor each.

The first sensor for (approx) 400nm - 470nm and a second from (approx) 620nm to 740nm. All want to do for this level is exclude the green and yellow between 470nm - 620nm. Many light charts I've seen show more than double the PAR watts as compared with PUR watts.

1/2 way done the page, sorry if I'm presumptuous:

http://www.aquabotanic.com/lightcompare.htm

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The light meter is to help me be sure that I'm getting the same intensity - at equal levels below the canopy - with LED as with HPS within the PUR watt range. I'm using standard LED panels and the focus of the experiment is on developing equipment to increase LED penetration while increasing coverage. Sort of like inventing a substance that cannot exist in our universe.

The first tests with an inexpensive Hydrogarden meter look promising, I am able to increase canopy penetration and light instensity using an LED flashlight as the light source.

Can Jaz modules accommodate sensors in the 400nm - 470nm and a second for 620nm - 740nm. Or anywhere close?

thanks again

Hobbes

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LED folks

What do you think of the Procyon 100? I'm thinking of getting two and hook them up end to end to get the 200W LED I need, add a 5" Par38 for the full 32". I can't find the right size anywhere and these look good on the surface.

What do LED knowledgeable people think of these lights? What option for a 32" x 200W LED would you suggest?











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Procyon 100W LED Grow Light




Features:

• 56 CREE* Xlamp high power LEDs (40 Red, 16 Blue)
• 100W nominal LED power delivery
• 125W total power consumption
• Integrated power supply; requires no “ballast”
• Replaces 400W HID light, giving 75% power savings
• Covers approximately 10 square feet
• 50,000+ hour LED life**
• Proudly Made in the USA!

Patents Pending. Measures 13.5" x 5" x 5", weighs 7lbs. MSRP is $599.

* Cree currently holds the world record for LED brightness and efficiency.
** 50,000 hour lifetime is defined by Cree as a 30% decrease in brightness. LEDs will still continue
to function long after the 50k hour milestone is reached.

All Procyon 100 lights ship with ~635nm peak and ~450nm peak wavelength LEDs.

The Procyon 100 is being sold at indoor gardening and hydroponics stores
across the US. Please check with your local store for availability. In addition
to these stores, it is available through these online retailers:

www.procyondepot.com

http://www.lowenergydesigns.biz/

This list will be updated regularly as new online vendors are added.
If you would like to become a distributor, please contact us!

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Hello Hobbes, this is an excellent goal to have for any & all in the growing LED community! I've followed many of your threads, they've helped me a lot!
I'd like to offer my observations on LEDs. I don't work for anyone & am a long time HID & fluoro tube man who'd like to contribute to a potentially superior new tech; (I bought a 180w 5-band UFO in February & have been quite impressed & learned a lot.)

First sir, I'd start by saying that unfortunately, building/having someone custom build you a high PPFD (High PUR wattage) LED unit is the best way to go IMO.

If you asked me who makes effective grow LEDs, The 2 I've seen used many times now for dense, robust nugs are Hydro Grow LED & ProSource. That being said, you could build yourself a superior lamp for half...

KNNA (member here) is working on a resale light that uses some of the highest efficacy (lumen/w, some whites 100+ lu/w!) emitters available in a very refined spectral ratio (how many reds, blues, deep reds/IR, whites, UV etc) to give you a dead on SPD.

Hopefully his & future LED will soon offer true HID-rivaling output per watt, but with virtually no wasted luminous flux! Imagine 90+% of the photons leaving a light being armor-piecing .50 caliber bullseyes fired into cannabis' PUR-range target... The lofty "2 grams/watt" mark could become like the old H.P. per inch^2 and more recently 100 hp/L in car engines.


Whoaa.. sorry, I'm zoned on Granddaddy Purp.. focus!


Many commercial LED grow lights are simply:

A.) Underpowered in Photosynthetic Photon Flux Density. Low-output and wide-angled emitters(120* vs 60 or 30*,) & electrical hardware not delivering advertised wattage/light are often why.
LEDs CAN penetrate, they just need properly-driven H.O. emitters.

B.) Do not produce a decently broad, natural SPD (spectral power distribution) like natual sunlight, CMH, premium HPS ect.

C.) Both A & B.. bummer.

D.) EXACTLY what your talking about! Not offering a focused LED array. IMHO mounting them on a shallow concave indent (think of inside a shallow bowl.. or Mag-Lite lens) atop a constant, reflective radius only makes sense, just figure optimal canopy height from the LED's total output & point the array of powerful desired degree-lens emitters at the same target (30, 60?) & Shazamm!!. No need for large traditional reflectors that eat precious photons.

I still think using a thin glass sheet in front of the reflectors is a convenient feature for cleaning. It will hurt output & UV transmittance but its WAY easier to clean then hundreds of little lenses!

Oh, I think your on the right track to getting MJ's PUR from PAR numbers. IIRC you would need to find or measure exactly what the PAR spectrum's wavelengths Pn absorption % is. Then quantify a value scale from the highest wavelength. There are a few dusty ole studies on this but a truly dedicated scientific research on cannabis' Pn PUR needs to be done. (Netherlands, Oaksterdam, CA... one of us?)

660nm Red LEDs seem a consensus winner for cannabis' Pn efficiency of Chlorophyll A (flowering) & 440nm Blues have rocked hard for Chrlophyll B (Vegging.)

But the really interesting part to me was mentioned earlier in this thread by purfict. The ability to adjust wavelength frequency! When this gets dialed in by the marine life crowd or us & the help of geeks, the possibilities explode!

*cash bowl, hydrate... focus!*

...Sorry for the fervent ramblings, I'm on an interstellar journey now!

But I'll leave you with what I feel could be the next big thing (once prices drop at least 50% )

Plasma LEDs. This one just needs more red bias & we might have the heir to incandescent HID's...

http://www.chameleongrowsystems.com/store/CGS-SG-II_MJ13_V7.html

IAm5toned said:

Led's emit a focused beam of light, an LED consists of 3 components- a diode, a resistor, and a lens. think of a simple flashlight, emitting a beam of light in the dark.

Photons travel in one direction, and one direction only. That direction is a perfectly straight line, the term 'ray' used in mathematics, describes the path of a photon perfectly.infinitly straight.

only a star has enough gravity to alter the path of a photon. and even then it is a very very slight bend, almost unmeasurable except over great distances.

Led's emit photons on a path perpendicular to the plane of the led (90 deg angle) this is achieved by the lens on the led. the diode itself emits light like any other substance,. its radiated. however the radiated light is weak, so it is focused and directed by the lens that caps the diode.

a good example of this principle is the headlights on your car... tiny lamp, burns bright but weak, is focused into a powerful cone shaped beam.... the center of the cone is packed very densly with photons, but as you get to the edges of the beam, the density very rapidly diminishes.

if you had magic photon glasses and happened to be looking at a led panel that was lit, it would look like it was standing on dozens of little cones, one cone for each LED in the panel.

And that is the flaw of the LED. the lens directs the emitted light in one direction only, down. (or wherever your pointing the panel at.)


now take your magic photon glasses and look at an hid lamp. you might want to crank the settings up on the glasses though first. the photon emission will look like a giant sphere, (like a star! like the sun!) the light is radiated in all directions at an intensity that is very dense with photons. photons are traveling at angles that are perpendicular to the core of the lamp. since the core of the lamp is gaseous, this singular point of emission is speherical in nature, so photons are emitted in all directions;

whereas in LED's the photons are focused into one direction. This deflection of light, coming from different angles, is what achieves canopy penetration, not the intensity of the hid lamp, which is almost universally assumed by many.

This is also the reason many people acheive success growing with CFL's and HO lamps... the light is emitted from more than one direction, just as found in nature.

If you could find a way to direct the LED light to the lower portion of the canopy, then i think a person could have great success with LED's, or perhaps build a cab with 360 deg LED lighting, then you might have something. ''

Click to expand...

back in a bit ... I want to ask some questions about led light diffusion and how the light beams or cones will be effected by distance and reflection.

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also, don't plan on growing a canopy much more than the size of the LED light. A bunch of spread out lights is better than if they are compacted into a small square area. having lights all around the plan is a must. and even if you were able to suspend some lights down into in the middle of the canopy is best.

one other thing about LED is that they can pulsed instead of continuously on, and save about 80% of the power, and work just as well for photosynthesis, and last longer, although no commercial units have this feature. there is a specific duty cycle and cycles per sec this must do, but there is research out there.

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I haven't been able to find the size light that I want and most light panels have several inches of frame around them which is no good for me either - I need light right to the end. So I'm going to build my own panel with Par38 bulbs and sockets on a stick.

The 38 after PAR is the diameter in inches when divided by 8, which makes perfect sense to me. 38/8 = 4.75". It couldn't be more clear, why wouldn't size be expressed this way?

I'm going to run several rows, with the circular lights offset to make a fairly solid rectangle. I would like to get 200 watts worth, fairly tight angle on the lenses for a tight light cone.

Here's a few I've been looking at, could you recommend the best you've seen and post a link please. Thanks.

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High Power 42 SMT RED LED PAR38 Grow Light Budding



Product Information


FEATURES: This PAR38 screws in any standard light socket and it works from 85 volt to 260 volt. No ballasts or transformer is required. It put out 10 times more light than a 5 mm LED.


BENEFITS: This PAR38 screws in any standard light socket and it works from 85 volt to 260 volt. No ballasts or transformer is required. It runs at a warm temperature rather than very hot which is common with most other inefficient plant lights. This more controlled running temperature reduces the need to water so often and keeps rooms with plant lights from getting uncomfortably hot in the summer months requiring additional air conditioning. This state of the art LED panel plant light is extremely energy efficient, paying for itself many times over annually in electricity savings. It saves 50% to 90% in energy consumptioncompared to incandescent bulbs or fluorescent tubes. Wide angle projection insures uniform leaf coverage. This specialty all Red LED grow light panel is designed to allow you to custom tailor the light spectrum for maximum flowering.


This powerful all Red LED Bulb has been scientifically designed to provide large illumination coverage of 2 square feet so it needs to be positioned at approximately 6-8" inches away from the plants. 12 hours per day is all that is necessary for maximum plant health to accelerate the flowering process. The typical white plant lights that run hot, consume excessive electricity wasting money. The purity of these All Red LED lights generates faster bud development, flower blossoming, fruit growth, health, beauty and productivity. These LEDs turn on instantly and can be turned on by hand each day or work well with all standard lamp timers.

We also carry all BLUE LED grow lights which are designed for maximum level photosynthesis food production and accelerated leaf growth.We also have blended Red and Blue LED grow light panels that have both wavelengths that are for accelerating growth and flowering.

Bulb Type
Standard Screw Base
Life time
50,000 Hours
Color
Red (650nm) View Angle
140 Deg
Light output
10 x brighter than 5 mm LED (300 Lumen)

Operating Voltage
90 – 260 Volt AC
Consumption
15 Watt
Product Diameter
4.75” or 120 mm

Product Length
4.5” or 114mm

Price: $62.00 $52.00

http://www.ledwholesalers.com/store/...&productId=287

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that is one perfect light! you will need to mix them with the blues...i think 8:1...i forget. GOOD FIND! These are like perfect...15watts and tiny. They are a little expensive though! But with your planning 200 watts worth and with 360 degree lighting...you will grow like you had a 400watt panel.

also i was thinking with the strobing LED you could put a capacitor in the circuit and then reduce the power consumption of the panel by like 80%. So you could get 1000watts of effective LED photosynthesis power and only consume 200watts, and I do not know how this affects LED life, increasing or decreasing.

Have a look at this on youtube,pretty amazing even if it is just a tomato plant Sunlight sheds 90w ufo they have 3 ufo's and 1 hps growing tomatoes side by side the ufo with 660nm red wins.I swear by my 400w hps but if leds come down in price I would get one.Dutch green grow lights do led lights and nutrients they claim are tailor made for led grows.

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I'm going to be using PAR instead of PUR, both because of: the prohibitive cost in a relatively inexpensive Jaz multi meter - about $5,000; and the lack of sensors in the spectrum we want - we'd get wavelengths outside of PUR anyway.

I can get a Field Scout Quantum Meter (PAR) with a remote sensor for $300. A PAR meter often gives measurements of double the PUR watts for many HID bulbs, this may cause me to over power the LED array but that should be a benefit. Then later I can reduce wattage if possible. I'll be ordering the meter tonight or tomorrow.



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Does anyone have an option for a PAR meter?

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I still have a few emails out to LED panel manufacturers but I believe that I'll be going with 4 x Lighthouse 90 watt UFOs to make my light panel (360 Watts). UFOs seem to give the best watts to the dollar (or dollars per watt most times), good value. I'm going with Lighthouse because they advertised 16,400 lumens - so I added up the lumens for the other UFOs and they were in the 3500-5000 lumen range. Good mix of wavelenghts, 6 bands.

• Diameter: 10.5 Inches
• Depth: 2.5 Inches
• Number of LED's: 90
• Total Wattage: 90
• Lifecycle: 50,000hrs
• 6 Band LED
• Deep Red LED: 660nm
• Mid Red LED: 630nm
• DEEP Ultra Violet LED: 380nm
• Infrared LED: 730nm
• HO Cree Blue/White 101 Lumens/led
• HO Cree HO White 111 Lumens/led
• SKU: LHH90WHO

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http://cgi.ebay.com/NEW-2010-model-90w-HO-Cree-Lighthouse-Hydro-6-Band-USA_W0QQitemZ270507614875QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3efb82a29b

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Does anyone have an option for UFOs? Anything you find better?

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I'm going to angle the UFOs like a roof over each of the two columns of plants, get the tops and the sides.



That will be 360 watts of LED, 180 watts hitting each plant. I'll put up a light barrier in the middle of this 8' x 3' cage and run my 360W LED array against 400W & 600W Hortilux Super HPS, side by side grows with paired clones going into flower at the same time, 6 strains per side in a continuous grow. Eventually I'm hoping to do the entire 8'x3' garden with 360 watts

15 watts LED per square foot down from 50w/'2 with my 1000W HPS in a 4'x5' garden is the final goal of this experiment.



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This has been the necessary but not really productive phase of the experiment - finding the proper measuring and lighting equipment, learning the terms so I can speak with knowledgeable people. Now that I'm pretty much decided on lighting and meter I'll start designing the adapter (read funnel), the frame for the UFO array, thinking about what kind of readings to take, what they'll mean, how the light receptors on the plant work, what they're made of, etc, etc.

Every time I answer one question I realize 3 more.

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HO Cree Blue/White 101 Lumens/led
HO Cree HO White 111 Lumens/led

seems like a waste of watts to get lumens

you should just get at maximum a 3 band

So are you going to cannibalize the UFO to use the LED bulbs that come in there to make your strip? Sounds like an interesting experiment you have going on. Definitely subscribing to this one. Good luck

Lots of good information here. I have a 300W and a 120W in the mail right now. My plan was to use the 300W up top and the 120W down bellow. they are replacing my 8 T5's that I've been using (which even though people tell me T5's suck I was happy getting 6oz every 2 months in a 4X2 space - more than enough for me to smoke). I was going to try and set up my T5's as I need them to fill in any shadowing or weak spots. I know HID HUT has a screw in bulb I was thinking about getting for sub canopy lighting. It was cheap due to old technology. They were like $10 each just under 2 watts. The difference is the new ones use 1 watt LEDs and this one used like 30 something like 0.2 watt LEDs. The new ones for $30 to $100each are either red or blue. The other one is mixed. For one small plant they might work (at work of for a small house plant on a desk), but I was going to try to use it for sub canopy lighting as the T5 penetration sucks I get about 8 - 10 inches of bud and after that nothing (great in a SOG - but Suck ass for anything beyond that). I just broke down and ordered the 300W led instead.

Keep up the good reading everyone

IAm5toned said:

hobbes- put this in your jar and let it cure for a min-

Led's emit a focused beam of light, an LED consists of 3 components- a diode, a resistor, and a lens. think of a simple flashlight, emitting a beam of light in the dark.

Now back to photons-
justthe facts left out a very obvious thing about the nature of photons. I will reiterate just for prudence's sake.
Photons travel in one direction, and one direction only. That direction is a perfectly straight line, the term 'ray' used in mathematics, describes the path of a photon perfectly.infinitly straight. only a star has enough gravity to alter the path of a photon. and even then it is a very very slight bend, almost unmeasurable except over great distances. einstein predicted this ages ago and it has been confirmed, those of us that follow physics know the rest of the story.

now on photons and led's-

Led's emit photons on a path perpendicular to the plane of the led (90 deg angle) this is achieved by the lens on the led. the diode itself emits light like any other substance,. its radiated. however the radiated light is weak, so it is focused and directed by the lens that caps the diode. a good example of this principle is the headlights on your car... tiny lamp, burns bright but weak, is focused into a powerful cone shaped beam.... the center of the cone is packed very densly with photons, but as you get to the edges of the beam, the density very rapidly diminishes. if you had magic photon glasses and happened to be looking at a led panel that was lit, it would look like it was standing on dozens of little cones, one cone for each LED in the panel. And that is the flaw of the LED. the lens directs the emitted light in one direction only, down. (or wherever your pointing the panel at.)

now take your magic photon glasses and look at an hid lamp. you might want to crank the settings up on the glasses though first. the photon emission will look like a giant sphere, (like a star! like the sun!) the light is radiated in all directions at an intensity that is very dense with photons. photons are traveling at angles that are perpendicular to the core of the lamp. since the core of the lamp is gaseous, this singular point of emission is speherical in nature, so photons are emitted in all directions; whereas in LED's the photons are focused into one direction. This deflection of light, coming from different angles, is what achieves canopy penetration, not the intensity of the hid lamp, which is almost universally assumed by many. This is also the reason many people acheive success growing with CFL's and HO lamps... the light is emitted from more than one direction, just as found in nature.

If you could find a way to direct the LED light to the lower portion of the canopy, then i think a person could have great success with LED's, or perhaps build a cab with 360 deg LED lighting, then you might have something. ''
But its hard to overcome physics...

Click to expand...

Question - do all those photons from the hps light, going in a 360 degree ball, do ANY good to the plants that sit UNDER the plant? the answer = no. The led answer is to have enough photons traveling IN THE DIRECTION OF THE PLANTS, ie a stronger beam of light, say instead of 1 watt you put in a 3 watt or 5 watt light - more photons, more penetration. A light mover with a properly designed led will outperform any hps, (if you take into account wasted electricity) because ALL the light of the LED is used to grow, while, unless you are doing a vertical stadium grow or something similar, approximately 60% of your HPS light is going to waste! Even if you are not doing a vertical grow, you still waste approximately 20% to the reflector, so while in point the argument is kind of valid, there are the undisputable facts of not all the hid light goes in the direction you want, while all the led does. The waste factor is not even taking into account the energy lost thru heat, either.