Lighting Website Updates
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hahnmeister
In Memoriam
causeofhim, I am very aware of Sanjay's website, but what I am asking for is something not found there. I am interested in comparative results of looking only at the PPFD of the 400-500nm spectrums in all the bulbs. Its a guess, but that might be more important than just PAR from 400-700nm.
moonpod, Dana Riddle's work, eh? Ill see if I can find it. Any clues as to where you might have seen it?
I didnt know that about Euro and Japanese tanks...do you know how they do it and what its used for? Im very interested.
Found this: http://www.reefs.org/library/talklog/d_riddle_042698.html
At one point Dana suggests that the replacement period for 10,000Ks is 6months, 6500Ks is 2 years...why? Well, the 6500K contains more blue to start with than a 10,000K. Very true, and it would support my idea as well...if blue light is the most/only important light. Ill keep digging.
Then this one says spectrum matters little (only intensity and flow), with a type of acropora nana however. But there is no scientific date to support it in the experiment.
moonpod, Dana Riddle's work, eh? Ill see if I can find it. Any clues as to where you might have seen it?
I didnt know that about Euro and Japanese tanks...do you know how they do it and what its used for? Im very interested.
Found this: http://www.reefs.org/library/talklog/d_riddle_042698.html
At one point Dana suggests that the replacement period for 10,000Ks is 6months, 6500Ks is 2 years...why? Well, the 6500K contains more blue to start with than a 10,000K. Very true, and it would support my idea as well...if blue light is the most/only important light. Ill keep digging.
Then this one says spectrum matters little (only intensity and flow), with a type of acropora nana however. But there is no scientific date to support it in the experiment.
Last edited:
causeofhim
New member
That is actually there also. Look at the spectrum plots that it links you to. You can compare these.
Also, that comment wasn't directed directly at you but, many people who ask without looking.
hahnmeister
In Memoriam
Yes, but that is just a visual representation. I would need not just a pic but some sort of access to the graph making program itself so I could calculate the integral of the curve in these sections to get an actual number that means something. From my understanding, the PPFD of a bulb is the area under the graph from 400 to 700nm...not just the linear measure of the peaks at certain wavelengths. I am most interested in the PAR / PPFD number from 400-500nm...not its graphical representation.
mwood
Premium Member
The graph came from the website from an article written in 1998. I'm not sure if he has anymore, but I do think these numbers would be a great addition to the data. I don't think the data completely supports your theory. Under your theory, radiumââ"šÂ¬Ã¢"žÂ¢s should outperform Iwasaki's for growth. I haven't heard any reports of this type. Quite the opposite, I read more about people liking the colors under 20k, but don't see as much growth.
johns
Premium Member
I don't think the data completely supports your theory.
hahn-
Tha'ts probably true. You seem to be one of few observing faster growth with higher k bulbs. By most accounts, people who have done the opposite (switching from 14k/20k to 10k) have seen faster growth. I myself am seeing a growth spurt on switching from 14K phoenix to 14K ushio (which is a actually a MUCH whiter bulb than the phoenix). However, I have to say that the phoenix bulbs were almost a year old and were starting to dim a bit. I might have experienced the same growth spurt had I simply switched to new phoenix bulbs.
Unfortunately, in this hobby, it's very difficult to control things to do proper experiments. So we see a constant barrage of people claiming that this bulb or that bulb, this K or that K, are the penultimate bulb. The best you can do is wade through it all and look for trends. Trend for growth seems to be in favor of lower K, IMO.
hahn-
Tha'ts probably true. You seem to be one of few observing faster growth with higher k bulbs. By most accounts, people who have done the opposite (switching from 14k/20k to 10k) have seen faster growth. I myself am seeing a growth spurt on switching from 14K phoenix to 14K ushio (which is a actually a MUCH whiter bulb than the phoenix). However, I have to say that the phoenix bulbs were almost a year old and were starting to dim a bit. I might have experienced the same growth spurt had I simply switched to new phoenix bulbs.
Unfortunately, in this hobby, it's very difficult to control things to do proper experiments. So we see a constant barrage of people claiming that this bulb or that bulb, this K or that K, are the penultimate bulb. The best you can do is wade through it all and look for trends. Trend for growth seems to be in favor of lower K, IMO.
hahnmeister
In Memoriam
mwood, I dont think that the radiums would overpower necessarily, but it would level the playing field a bit. The 6500K has more 450nm purple than a radium, and the radium has more 450nm blue...so they are about even.
My point isnt so much that bluer bulbs work better, or yellower ones...etc. Its that if you look at one bulb compared to another...the strong growers seem to all have large amounts of blue despite all the other spectrums they produce.
Take the 6000K...from what I have heard, it is a horrible grower. Then you have the Aqualine 10,000K. IME, it was as well.
I suppose the only way to prove it would be two tanks...one with nothing but actinics and 420nm blue bulbs (perhaps my T5 fixture), and another with nothing but yellow halides or halogens...matching PAR to PAR. Sure, the spectrums might not be as narrow as we would like, but both would have about the same 'leakage' of other spectrums so its rather fair. And then place identical frags in each tank and see which grows better if at all. Does anyone see any flaws with this?
My point isnt so much that bluer bulbs work better, or yellower ones...etc. Its that if you look at one bulb compared to another...the strong growers seem to all have large amounts of blue despite all the other spectrums they produce.
Take the 6000K...from what I have heard, it is a horrible grower. Then you have the Aqualine 10,000K. IME, it was as well.
I suppose the only way to prove it would be two tanks...one with nothing but actinics and 420nm blue bulbs (perhaps my T5 fixture), and another with nothing but yellow halides or halogens...matching PAR to PAR. Sure, the spectrums might not be as narrow as we would like, but both would have about the same 'leakage' of other spectrums so its rather fair. And then place identical frags in each tank and see which grows better if at all. Does anyone see any flaws with this?
Sanjay
Premium Member
Hahnmiester and others in this discussion,
Ideally it would be really nice if we had a really good idea of what parts of the radiation (400-700nm) do the corals actually use and how much of it.
Unfortunately, there seems to be a wide range of useable light spectrum given the corals ability to adapt and the wide range of different zooxantalle and pigments in the corals. There are some general descriptions of the absorption spectra that show the light spectrum the corals use.. however its not constant for all corals at all depths.
Assuming you had a good absorption spectra, you could theoretically multply a normalized absorption spectra with the lamps spectral distribution and compute the PUR (photosynthetically useable radiation). I have done this with a absorption curve that was given to me by charles mazel. Interestingly for this absorption curve.... lamps with higher PAR had higher PUR too. I know steve tyree has a absorption curve that he has derived from various pigment absorption curves, and I am absolutely sure that if I computed the PUR using his curve the results would be quite similar.. lamps with higher PAR would have higher PUR.
The other issue is that we do not know how much of incident light is being used. Clearly the corals are not using all the blue light that falls on it... otherwise they would not appear blue. We see the reflected color.
I know Dana Riddle has done some experimentations and reported the results in Advanced Aquarist (see the archives) that for broad spectrum lighting, PAR is strongly correlated to growth. So from the growth perspective it seems that the more PAR the better. However, it may be better to have that PAR spread out over a broad region of the spectrum rather than having it concentrated in a narrow regions.
However, when it comes to visual appeal and the development of pigments that we as humans prefer to see, the higher K lamps seem to do a better job. I however do not like the look of a blue tank, others do. I do not even run actinics over my tanks.
I think it is pretty much established by anecdotal evidence that with any of today's MH lamps from 6500K - "20000K" corals can be grown. So the basic rule of thumb is "use the highest rated PPFD for the lamp class of your choice". The higher the values of a lamp in a given class the higher the probability that it will last longer, since it has higher values and more room/time to degrade.
Clearly, lamps with most of the output in the "blue" range tend to have a shorter life since the metal halide used to generate the blue spike tends to degrade faster and lamps hence lamps loose thier output faster. Its a choice you have to make using your own value system, no one can make it for you.
Not sure if it answers all the questions.. but I am not even sure I can answer all the questions.
There is a lot we do not know and I would love to get that data if we can.
sanjay.
Ideally it would be really nice if we had a really good idea of what parts of the radiation (400-700nm) do the corals actually use and how much of it.
Unfortunately, there seems to be a wide range of useable light spectrum given the corals ability to adapt and the wide range of different zooxantalle and pigments in the corals. There are some general descriptions of the absorption spectra that show the light spectrum the corals use.. however its not constant for all corals at all depths.
Assuming you had a good absorption spectra, you could theoretically multply a normalized absorption spectra with the lamps spectral distribution and compute the PUR (photosynthetically useable radiation). I have done this with a absorption curve that was given to me by charles mazel. Interestingly for this absorption curve.... lamps with higher PAR had higher PUR too. I know steve tyree has a absorption curve that he has derived from various pigment absorption curves, and I am absolutely sure that if I computed the PUR using his curve the results would be quite similar.. lamps with higher PAR would have higher PUR.
The other issue is that we do not know how much of incident light is being used. Clearly the corals are not using all the blue light that falls on it... otherwise they would not appear blue. We see the reflected color.
I know Dana Riddle has done some experimentations and reported the results in Advanced Aquarist (see the archives) that for broad spectrum lighting, PAR is strongly correlated to growth. So from the growth perspective it seems that the more PAR the better. However, it may be better to have that PAR spread out over a broad region of the spectrum rather than having it concentrated in a narrow regions.
However, when it comes to visual appeal and the development of pigments that we as humans prefer to see, the higher K lamps seem to do a better job. I however do not like the look of a blue tank, others do. I do not even run actinics over my tanks.
I think it is pretty much established by anecdotal evidence that with any of today's MH lamps from 6500K - "20000K" corals can be grown. So the basic rule of thumb is "use the highest rated PPFD for the lamp class of your choice". The higher the values of a lamp in a given class the higher the probability that it will last longer, since it has higher values and more room/time to degrade.
Clearly, lamps with most of the output in the "blue" range tend to have a shorter life since the metal halide used to generate the blue spike tends to degrade faster and lamps hence lamps loose thier output faster. Its a choice you have to make using your own value system, no one can make it for you.
Not sure if it answers all the questions.. but I am not even sure I can answer all the questions.
There is a lot we do not know and I would love to get that data if we can.sanjay.
E-A-G-L-E-S
New member
Sanjay...are you going to march ncpars meeting?
any future chance of the 250W 12K CoralVue ReefLux lamps getting tested?
happy reefin
any future chance of the 250W 12K CoralVue ReefLux lamps getting tested?
happy reefin
Travis
10 and over club
I don't think too many people will have any experience (unless it was accidental) because DE bulbs produce dangerous UV rays that will burn your corals. That is why you need to run the glass lens. SE bulbs have an outer glass envelope that filters out their harmful UV rays and that is why it is not a requirement to run a glass lens with them.
hahnmeister
In Memoriam
I have a friend using hamilton 250wattDE pendants over his 120. Oddly enough, the glass in there isnt labelled as LoE or anything that screens UV like my PFO pendants do. Anyways, he was using nothing but 10,000K Ushios until recently when the shipper sent him the BLV 12,000K bulbs. Oddly enough, many of his corals towards the top of the tank are dying off...looking like they are bleaching. I suspect that the Ushios are a brand of DE that still has the UV-quartz sleeve, and the new BLVs dont...and some kind of UV is getting thtough the glass and frying his corals. But that is pure speculation on my part...
I have a Q Sanjay. When I go to the 'compare 2 lamps' and compare spectral plots...
The Ushio 10,000K, DE, 250wattPFO ballast, sheilded, to the Radium 20,000K, SE, 250wattPFO ballast, non-sheilded...I get on type of spectral graph for the Ushio.
BUT, then I put sub in the Aqualine 10,000K, DE, 250wattPFO ballast, sheilded, and keep the Ushio's parameters the same...and the resulting spectral plot for the Ushio changes.
Any reasoning on that? Then..once again leaving the Ushio alone, I plug in the EVC 10,000K DE, and the Ushio appears to have a different spectral plot yet again!
I am confused...what is the real spectral plot of the Ushio?
I have a Q Sanjay. When I go to the 'compare 2 lamps' and compare spectral plots...
The Ushio 10,000K, DE, 250wattPFO ballast, sheilded, to the Radium 20,000K, SE, 250wattPFO ballast, non-sheilded...I get on type of spectral graph for the Ushio.
BUT, then I put sub in the Aqualine 10,000K, DE, 250wattPFO ballast, sheilded, and keep the Ushio's parameters the same...and the resulting spectral plot for the Ushio changes.
Any reasoning on that? Then..once again leaving the Ushio alone, I plug in the EVC 10,000K DE, and the Ushio appears to have a different spectral plot yet again!
I am confused...what is the real spectral plot of the Ushio?
hahnmeister
In Memoriam
Sanjay, ah..its scaling. Wow...I will have to take that into consideration from now on.
I will double check, but I am sure its is a 12,000K...some new bulb...pretty sure he said BLV.
I will double check, but I am sure its is a 12,000K...some new bulb...pretty sure he said BLV.
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