TheMadNucleus - A moment of your time if you don't mind

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
B

Bang Guy

Aquarium Advice FINatic
Joined
May 22, 2002
Messages
610
Location
Western NY
Hi Tom,
I didn't want to hijack that thread but I would like to learn more about what you've stated.

Everything I've read about the Kelvin temp of bulbs points to what I stated in that Actinic thread.

If I'm wrong I would like clarification so that I don't state inaccuracies in the future.

Please explain why these are incorrect. I appreciate the time.

1 - It is my understanding that no matter how hot you get a black body it will not produce light as energetic as 420 nm. Therefore, I believe that 420nm does not have a Kelvin temp rating.

2 - Everything I've read has stated that the Kelvin Color scale has a maximum of 20,000K and this is in the blue range.

3 - I've read that 320 - 400nm is in the UV-A range and is invisible to the human eye.
 
Hi BangGuy,

I think there is a bit of misinformation about this but here is a site that has an intereactive tool which makes te relationship between this stuff pretty clear:

http://skyserver.fnal.gov/en/proj/advanced/color/physlet/blackbody.asp

Basically this is a simple scoop. The balck-body approach: This is based on a theoritical object which produces no inherent radiation of its own (some people erroneously assume this is black metal - though not exactly correct it is an easy way of looking at it. So you take this object and start heating it up. As it heats it starts to radiate. At lower temperatures it radiates low frequency (large Wavelength) radiation and as you heat it it continues through the radiation spectrum something like this:

Eimts from coolest to hotest, temps are approximates:

Radio Waves 1000K
Microwave
Infared Waves (i.e. below red or below visable spectrum) 2000K
Visable Light (4500k-7200K)
Ultraviolet (7500K - 20,000K)
X-ray (25,000K)
Gamma rays (30,000K +)

The temperatures provide for lightbulbs and the wavelength definitions are specifically peak outputs - i.e. where in the light spectrum the bulb will have its greatest output. This can be provided as a temperature (relating to a heated black body which would have the same peak - though not neccessarily the same color mix) or the specific wavelenght. The spectrum a bulb emits is usually referred to as the CRI (color rendering index) but let's leave that out for a moment.

The reason that actinics are not given in kelvins is that they typically are very narrow bandwidth i.e. they filter much of the output arround the peak wavelength - however, that does not mean that they don't have a peak wavelength or that the peak wavelength can not be directly related to a black-body object. The difference being that all the other wavelengths in the spectrum of an actinic are missing were as they are there in a black body object.

np on hijacking the thread - your input was valuable I just did not want folks to get a misunderstanding that the formula doesn't work - it does but the actinic bulbls are a bit of a special case and one has to be aware of how to apply the formula.

In my post by saying the bulb has a temperature of 6900K - I meant it has a peak output which would match a full spectrum bulb at the same temperature. Usually the peak is what we are interested in for organism health not so much for appearance - just so happens that many like the blue/violet tint of some of these bulbs as well. :)

Well - hope I helped and didn't add anymore confusion and I hope you enjoy the site I've posted.

Tom
 
Hey yaksplat - what's up - haven't seen you around much.

Don't like the cameraguild post - oversimplifies and misses a few important factors.

Like the second one - must use the same appelet as the one I posted :)

thanks for the additional info.
 
Thanks for the help.

I'm in understanding of Wein's Law as it relates to Black Body but I meant to say that I can't see how it can apply to monochromatic light output like a an 'actinic' bulb where there's basically light from 400nm - 440nm but almost nothing else and a huge peak at 420.

I think the formula works for MH bulbs very well because the light is actually produced mostly by heat (some phosphors) but monochromatic flourescent bulbs just don't fit when the light is indirectly produced by exciting phosphors with UV light.

Hope I didn't come across wrong. I'm just always looking to learn.

Thank you!
 
I haven't done any new DIY stuff for a while. I've been busy trying to figure out what exactly is in my tank. So many animals, so little time.

well, given the name Cameraguild, i knew that some of the physics of it would go right out the window. I was attempting to find sites that had nothing to do with cameras. I did like the graphs on this page.


So the question is, what is the optimal temperature bulb?

Does actinic filter the light, or produce light in the correct spectrum?
If actinic filters the light, then the remainder is being dissapated as heat instead of visible light. Wouldn't the organisms tend to use the portion of the spectrum that they need? Or do they need to be pummeled with that certain wavelength.

If we want to have our peak wavelength be at 420nm, then the color temperature should be around 7000K.

am i wrong?

Jim
[/img]
 
Yaksplat,

Some very good questions - some of mine as well. Actinics don't really filter but use gas combinations to get the phosphorous to emit a very specific band of light (narrow spectrum) - i.e. like mecury vapor in a standard flourescent and Argon and Halide in a MH bulb. Funny thing about these bulbs are that flourescents and MH are very similar in concept and infact both are gas-discharge bulbs but both use different ignition methods and different gas combinations.

I'm not so sure about what our reluctant charges really need, I guess it varies but I sort of think that we should attempt to replicate what they are exposed to in the wild rather than do stuff which makes them glow :)

Yep, your conversion is correct. Just always have to consider other stuff when using temp. even for MH bulbs - they do not give the same color spectrum as a black-body - it is only the peak that this relates to. You can tell this because a 20,000k object really will have very little visible light - but 20,000k MH's have tons of visible spectrum and with a very wide bandwidth (i.e. close to white light).

Tom
 
Hey Tom,

I appreciate your comments on this. I think I understand better than before and that's always a good thing. Thanks for taking the time.

Yak - Actually, corals, or more precisely their zooxanthellae, can adapt to just about any light in the visual spectrum. It's not instant though. If you change the spectrum of your bulbs you should wait a week or two before judging the effect. I've heard theory that there are many species of zooxanthellae and each take advantage of certain wavelengths. I've also heard the other theory that zooxanthellae can actually adapt to different light sources.

bottom line - setup your lights with the look you like and let the corals adjust.

Actinic is just a made up name that Phillips lighting coined for one of their photo processing bulbs. In the hobby it refers to a bulb that produces light that peaks around the 420nm wavelength.

There are quite a few PC bulbs that just filter the light. the 7100K actinic is a primary example. These should be totally avoided IMO. They produce very little PAR compared to their true actinic counterparts that produce the light using rare earth phosphors.
 
Menagerie, I have to agree with you...I am totally awed now! It's so great to have folks on here who really understand the science behind this stuff and are willing to take the time to explain it to those of us who don't. Kudos to all three of them!
 
Okay, if our tanks need certain wavelengths, then the question is, does it matter what produces them? With the bulbs tranforming the electricity to light and heat, wouldn't it make sense to use a bulb that has the highest light to heat ratio? With the amount of heat that halides produce, it seems like a lot of electricity is being wasted. I know that the three of us all live in NY, so we suffer from the same high cost electricity.

With this in mind, what is wrong with lighting a tank with LED's? If the correct spectrum is there, but there is no heat I would think that this could work. I'm not talking about 10-20 LED's here. I'm thinking an array of 100 or so, with a combination of white, blue and UV, all over a 55 gallon tank. If this would work, can you imagine how bright and low cost this would be? For about $110, you could have 1.2x10^6 mcd beaming down on your tank.

I guess i'm just trying to get the most bang for my $0.13/kWH

I'd like to test this out in a small tank with a low light coral, or just a small piece of LR to try and get coralline algae growth, or even algae for that matter. I know LED's are relatively new, but have they been tested with plants?


Jim
 
So Jim, what would a 20" X 12" panel cost me? And how much power would three of these panels consume? Can the shape be tailored for a bowfront?

I'm changing out my lighting in the next month or two.

Can you just pop out LED bulbs and swap them to change colors?

Do they come in the near UV like 420nm?

If so I would be willing to Guinea Pig a project.
 
One more question. Can the panels be plugged into a dimmer switch? From what I understand LEDs are dimmable.
 
It would take some R&D to figure out what it would take to get the correct color scheme. But for a rough estimate, you could figure $.75 for each LED.

I'd like TMN to chime in on this one. I know he knows how to dim using a 555 chip as a pulse generator.

The UV LED's have a peak wavelength of 395nm and the blue LED's have a peak at 470. With a combination of these 2 and white, I think a broad spectrum could be achieved. I have a few at home, but I haven't wired them up yet. I'll have to pick up a breadboard just for some easier prototyping
 
Hi folks,

First off - Loganj - thx for the kudos.

Hey Jim and Bang Guy - I've looked into the LED solution - I think we have to wait a bit for higher intensity units to be available. The Spectrum is there (as jim pointed out, but they can be even of smaller wavelengths - i.e. hotter K's), in fact some Blue or white Light LEDs are in the 7000K to 10,000K temp range. But the output of these units is still very low in comparison to the level of light amplitude provided by a 175w MH.

I think we would need 1000's not 100's of these to even come close to the required output, not sure, though an experiment may be in order (yes Jim? :) )

I think our hope for this one lies in this company as they are on the fore-front of high intesity LEDs. They do manufacuter LED arrays but still their output I think is very low.

http://www.luxeon.hu/docs/emitter.pdf

Note the color temps for some of these (though I'm not sure about the CRI - Color rendering index) but surely the peak is in the right place. As a note for Bang Guy who was pretty interested in this, as you can see, LED's have no heated element, in fact they generate photons electronically and give off very little heat as Jim mentioned and yet their light output is measured on the Kelvin scale.

I've been watching for ways to get the extrodinarily high light output from LED's. Someone, a while back posted a reference to an article on this and I quickly did some research on it but only found theoritical stuff and forecasts for the next 5 to 10 years. :(

Anyway - like this thread - unfortunately, work beckons - chat soon.

Tom
 
Interesting....
Although their prices are waaaaaay up there, 200 euros for a 12 emitter ring. They advertise no UV in their emitters, but I believe that in our situation, we would like some.

The few moonlights that i have in my tank are rated at 2600 mcd. FWIW those are extremely bright. I can't imagine an array of 100, 12000 mcd, LEDs. The photon pressure alone should be enough to pin a fish against the substrate. :lol:

If you understood that one, thanks for joining me in nerdville :)
 
After reviewing several sites devoted to LEDs this is pretty exciting. But I have to agree with Tom, looks premature. The LED Tape is REALLY cool stuff though!!!

My concern right now is corrosion. It looks like the emitters last a lifetime but I'm concerned about all of those metal connections in a high humidity warm salty environment.

Guess it's back to MH for at least a few more years.
 
I thought of that when I did my moonlight setup. I have everything buried under a layer of silicone. The only thing that is exposed is the plastic lens.
 
On most aspects of this hobby I pride myself in the fact that I have more of a grasp than the average person and try to pass it along when I can. But when it comes to light...I am totally clueless. I read the above post...wow...I'm confused and dont even know where to start. This is a topic that I'll be looking into more. Thanks for the info.

Squishy
 
You must log in or register to reply here.

Similar threads

J
My complete knowledge and experience fighting algae for 15 years. Part 1 of 2
Replies
15
Views
16K
Stacey W.
Stacey W.
G
Handful of Q's from a n00b...
2 3
Replies
41
Views
2K
Gordo15
G
bosoxlobsterman
Fish in a high CO2 environment (such as if your CO2 is left on overnight)
Replies
12
Views
2K
bosoxlobsterman
bosoxlobsterman
brimac41
Those moments that make you shake your head
2 3
Replies
47
Views
5K
ccross
ccross
V
A question about temperature and chillers
Replies
9
Views
821
melosu58
melosu58

Latest posts

Back
Top Bottom