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hahnmeister · 11/17/2007, 01:17 AM

1. Those numbers are meaningless.

2. Still meaningless. Like saying 'you need 2000 calories'. Huh? For what? Per day, per hour? In this case, the light that may happen in nature at the water surface is a useless statistic for our captive systems. Only very large public aquaria actually need lighting that creates intensity at the surface as high as in nature. Most of our tanks have intensities that are a fraction of that because the light innt penetrating 5-25 meters!!! Its going 4-24" usually. So to tell people that they need some 'golden number' like 1800 whatever is completely useless, and false. Every tank will have different ideal intensities at the surface depending on the height of the tank, and the spread of the light source. For instance, a PFO mini-pendant halide can have a hot-spot of over 2000 at the water surface right under the bulb. Then, that same bulb, just as far from the surface in a lumenarc style reflector might only have a peak reading of 1200 at the surface. Yet, if you go down into the tank 2', the lumenarc will be more intense... how is that? You should look into dispersion fields, optics, and the inverse square law to correct this.

3. same as above really.

4. halides dont contain phosphors. 175s can last alot longer than that as well.

5. The sun produces 1800 where? And what does that have to do with the price of cottage cheese in China? And to say that T5s or other phosphor based bulbs with their PARs seem low it completely misunderstood and innacurate. There are plenty of T5s that can give halides a run for the money. The difference is that T5s and other tube bulbs are more spread out... so you will get a higher reading close to a halide bulb than you will a phosphor/tube bulb because the source is more concentrated with a halide. In order to compare them with accuracy, you need to measure them at greater distances without reflectors.

6.3, no that person was not confused... PAR is visible light output. Usually it is given from 400-700nm, just like the photometric scale. Shame on you for now telling them they were confused when you were the one who was/is.

6.4, you cant manipulate PAR like that. PAR, as you stated yourself, is a pure measurement that is evenly distributed. So a bulb with high amounts of blue will not give a 'manipulated reading'.

6.5, rubbish, just rubbish.

6.6, more meaningless stuff.

6.7 Kelvin ratings are not coordinate temperatures. They are arbitrary numbers for marketing. You are talking about the CCT. you will also find from the multiple spectrum graphs that Dana and Sanjay have published that red light drops off rapidly under water, even at just 5m. And then green as well. Since most corals we keep are from 5-25m depths, keeping them in bluer light is right on the money.

6.10, spectral graphs provide absolute outputs. See those numbers on the left hand side of the graph... those are actual exact amounts of radiation. They are not 'relative amounts' as you say. PAR/PPFD, for instance, is the integral of a spectral graph (a measure of the area under the line from 400-700, or 300-800 for extended range, for a total output).

I was unaware that LED's had problems with 475m light... that is blue light (450-495) by the way. Many LED's have this spectrum.

7. "I have no interest in the visual aspects of light when I speak of lumen"... thats just plain funny right there. Im holding my gut in. You pretty much just said "I have no interest in how many miles per hour Im going when Im talking about speed"...lol. Maybe you dont concern yourself with the visual aspects, but the lumen scale IS exactly that... lol.

Oh, and you cant 'fool a PAR meter' by loading up on one spectrum. Who told you that? Sure, a bluer light will have a higher relative PAR to lumen ratio than a warmer light, but thats not a form of manipulation. Its the true reading (unless its a crappy Quantum meter that has a faulty pickup at some wavelength, but thats not the radiometric scale were talking about then.

"I just haven't seen academic research showing the PAR requirements for each type coral.

I am sure Dana Riddle lives up to his reputation and would urge him to publish in the academic world so we can all see his methodology and analysis. With his experiments, Marine Biology would gain much."

Okay... like I said... have you even heard of Dana Riddle? He has been publishing here (www.advancedaquarist.com), almost every month or so, on spectrum, intensity, etc.

http://www.advancedaquarist.com/sear...ct=Dana+Riddle

You pretty much just walked into the Harley dealership and commented that you dont see any motorcycles with that one.

And then there is everything in this thread that I have already commented on.... like how you cant get a total efficiency rating of a bulb with your methods (I cant even do that... its so hard to do its not even funny... special room, equipment, computers).

11/17/2007, 01:17 AM	#61
hahnmeister Moved On Join Date: Sep 2005 Location: Brew City, WI Posts: 10,156	1. Those numbers are meaningless. 2. Still meaningless. Like saying 'you need 2000 calories'. Huh? For what? Per day, per hour? In this case, the light that may happen in nature at the water surface is a useless statistic for our captive systems. Only very large public aquaria actually need lighting that creates intensity at the surface as high as in nature. Most of our tanks have intensities that are a fraction of that because the light innt penetrating 5-25 meters!!! Its going 4-24" usually. So to tell people that they need some 'golden number' like 1800 whatever is completely useless, and false. Every tank will have different ideal intensities at the surface depending on the height of the tank, and the spread of the light source. For instance, a PFO mini-pendant halide can have a hot-spot of over 2000 at the water surface right under the bulb. Then, that same bulb, just as far from the surface in a lumenarc style reflector might only have a peak reading of 1200 at the surface. Yet, if you go down into the tank 2', the lumenarc will be more intense... how is that? You should look into dispersion fields, optics, and the inverse square law to correct this. 3. same as above really. 4. halides dont contain phosphors. 175s can last alot longer than that as well. 5. The sun produces 1800 where? And what does that have to do with the price of cottage cheese in China? And to say that T5s or other phosphor based bulbs with their PARs seem low it completely misunderstood and innacurate. There are plenty of T5s that can give halides a run for the money. The difference is that T5s and other tube bulbs are more spread out... so you will get a higher reading close to a halide bulb than you will a phosphor/tube bulb because the source is more concentrated with a halide. In order to compare them with accuracy, you need to measure them at greater distances without reflectors. 6.3, no that person was not confused... PAR is visible light output. Usually it is given from 400-700nm, just like the photometric scale. Shame on you for now telling them they were confused when you were the one who was/is. 6.4, you cant manipulate PAR like that. PAR, as you stated yourself, is a pure measurement that is evenly distributed. So a bulb with high amounts of blue will not give a 'manipulated reading'. 6.5, rubbish, just rubbish. 6.6, more meaningless stuff. 6.7 Kelvin ratings are not coordinate temperatures. They are arbitrary numbers for marketing. You are talking about the CCT. you will also find from the multiple spectrum graphs that Dana and Sanjay have published that red light drops off rapidly under water, even at just 5m. And then green as well. Since most corals we keep are from 5-25m depths, keeping them in bluer light is right on the money. 6.10, spectral graphs provide absolute outputs. See those numbers on the left hand side of the graph... those are actual exact amounts of radiation. They are not 'relative amounts' as you say. PAR/PPFD, for instance, is the integral of a spectral graph (a measure of the area under the line from 400-700, or 300-800 for extended range, for a total output). I was unaware that LED's had problems with 475m light... that is blue light (450-495) by the way. Many LED's have this spectrum. 7. "I have no interest in the visual aspects of light when I speak of lumen"... thats just plain funny right there. Im holding my gut in. You pretty much just said "I have no interest in how many miles per hour Im going when Im talking about speed"...lol. Maybe you dont concern yourself with the visual aspects, but the lumen scale IS exactly that... lol. Oh, and you cant 'fool a PAR meter' by loading up on one spectrum. Who told you that? Sure, a bluer light will have a higher relative PAR to lumen ratio than a warmer light, but thats not a form of manipulation. Its the true reading (unless its a crappy Quantum meter that has a faulty pickup at some wavelength, but thats not the radiometric scale were talking about then. "I just haven't seen academic research showing the PAR requirements for each type coral. I am sure Dana Riddle lives up to his reputation and would urge him to publish in the academic world so we can all see his methodology and analysis. With his experiments, Marine Biology would gain much." Okay... like I said... have you even heard of Dana Riddle? He has been publishing here (www.advancedaquarist.com), almost every month or so, on spectrum, intensity, etc. http://www.advancedaquarist.com/sear...ct=Dana+Riddle You pretty much just walked into the Harley dealership and commented that you dont see any motorcycles with that one. And then there is everything in this thread that I have already commented on.... like how you cant get a total efficiency rating of a bulb with your methods (I cant even do that... its so hard to do its not even funny... special room, equipment, computers). Last edited by hahnmeister; 11/17/2007 at 02:17 AM.