LED Spectrum?

[drtrash]

The first attempt casued the disco ball but by removing a red & green and adding 4 royal blue it helped blend the color. Also put the color led on a seperate driver for dimming and kept the violet on a seperate drive at100%. Also a diffuser cover & shadowbox was the icing on the cake. Thanks for all your posted info

 

[ReefLEDLights]

Can someone point to any place that shows UV helps? I know Actinic/Violet (420nm) helps, but all the articles I have read say UV does not help at all, actually hurts corals (under 400nm), yet, I keep seeing people recommend UV LEDs and I am so confused.

Feature Article: Playing With Poison - Ultraviolet Radiation — Advanced Aquarist | Aquarist Magazine and Blog

I like the 410-420nm UV. They do little for growth as they are dimmer than the XT-E Royal Blue but they do excite certain pigments in the coral to make them look better.

Totally agree that any thing less than 400nm is bad.

Bill

 

[Ace25]

See, that is my issue, calling 410-420nm light "UV" when it isn't. I wish people would get that part straight because it is really confusing the newbies. UV light is anything below 400nm in wavelength. I don't ever remember people calling Actinic T5HO bulbs "UV" bulbs, so why are people doing it now with LEDs? Just trying to clear that up for people reading this because it is 2 completely different light spectrums, one is bad (UV), the other is good (Actinic).

 

[greydmv]

See, that is my issue, calling 410-420nm light "UV" when it isn't. I wish people would get that part straight because it is really confusing the newbies. UV light is anything below 400nm in wavelength. I don't ever remember people calling Actinic T5HO bulbs "UV" bulbs, so why are people doing it now with LEDs? Just trying to clear that up for people reading this because it is 2 completely different light spectrums, one is bad (UV), the other is good (Actinic).

So are you saying sub 400 "UV" is bad "UV"? And that the lower 400 is more "Actinic"?

 

[Ace25]

All UV is BAD, but all Ultra Violet light ranges from 10nm up to 400nm. There is no UV light coming out of a 410-420nm LED. I know, it is such a small difference in wavelength, but it is a very important difference.

Ultraviolet - Wikipedia, the free encyclopedia

Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV. It is named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the colour violet. These frequencies are invisible to humans, but visible to a number of insects and birds. They are also indirectly visible, by causing fluorescent materials to glow with visible light.

 

[greydmv]

The first attempt casued the disco ball but by removing a red & green and adding 4 royal blue it helped blend the color. Also put the color led on a seperate driver for dimming and kept the violet on a seperate drive at100%. Also a diffuser cover & shadowbox was the icing on the cake. Thanks for all your posted info

Dtrash- do you have pictures of the finished product?

 

[ReefLEDLights]

The term UV in LEDs is a generic marketing term used by different companies.

Bill

 

[Ace25]

The term UV in LEDs is a generic marketing term used by different companies.

Bill

That is the problem I have, some companies call their 420nm LEDs "UV", while others call them Violet or Actinic. You can purchace 395nm UV LEDs just as easily as 420nm LEDs today, so calling every LED below royal blue "UV" is really confusing to people that don't understand lighting that well and can potentially lead to someone making a light with a lot of UV (395nm) LEDs and end up killing their entire tank because of it. I really wish they would stop using the term UV unless specifically speaking about sub 400nm wavelengths (the ones that are not visable to the human eye).

 

[cubsfan16]

It appears that people/vendors are using UV and Violet interchangeably. Look at many of the online LED sellers "UV" LEDs and you will see the have 410-420 violet spectrum.

 

[cubsfan16]

Oops....didn't see Bills response.

 

[stephnjeph]

Okay.. to answer your question, I will break down what i feel are the two most important values when building or choosing LED lighting for your home aquarium. I am sure most other lighting professionals will concur. First I will attepmt to explain the spectrum of light at various depths in the natural ocean. The most commonly used unit of measurment pertaing to the spectrum of light (also know as the temperature of light) is the Kelvin. At 0 degrees Kelvin, there is no light. Moving up the scale from 0 is when light is produced. As light waarms from 0, red light is produced. As the light grows in warmth, starting with reds, it continues on to greens followed by blues and then violets. The sun itself at mid day produces an approximate 5500k. The higher the kelvin, the greater the warmth of light. In nature at a depth of 15 feet the majority of reds and oranges are absorbed by the water. Continuing to a depth of 30 feet yellows are then absorbed. At 50 feet the greens have been absorbed leaving only blues and violets. Beyond 50 feet light will be at its highest kelvin until it eventually tapers off into the depths. Though Kelvin measure the color temerature of light, there is another means of measuring the intensity. LUX is the intensity of light that impacts any surface. In impacting water, LUX helps us determine the penetration of light. The sun itself produces 120,000 LUX, but due to changing weather patterns and such, it would average at around 75,000 LUX. As light hits the surface of water, wavelengths are absorbed and the intensity of light slowly dissapates into the deep. The clarity of your water will effect the penetration of your lighting. That is why water changes are so very important to good light penetration. There are LUX meters out there some cheap and some not so cheap but most being relativly accurate. But if you do not have a meter or are trying to calculate intensity before setting up a fixture, i can kind of help with that. In relativly clear water, light intensity at 15 feet will average 20,000 LUX, at 30 feet 10,000 LUX, and so on... Knowing where your corals grow in nature will help you determain what type of light temperature (kelvin) and intensity (LUX) they will require in your home aquarium. In figuring this, we will convert the wattage of our fixture at surface to an approximate LUX.


1 LUX = 1.46 milliwatts of energy at a standard 555nm with a light surface of 1 meter

or

1LUX = 0.00146 watts/sq. meter at 555nm

or

1 LUX = 0.0001389 watts/sq foot at 555nm


The only problem with this basic calculation is that the lighting of your home aquarium emits many differant frequencies leaving us no fool proof algarythym to calculate to exact LUX of our home aquarrium with out the use of a test kit. But we can use this simple method to approximate a lux reading without having installed a fixture. The LUX also determains how high above the surface water our fixture will need to be mounted. You will need to factor in your tank dimensions as well as the arc of light your fixture produces in order to assume a more accurate figure. Most coral we collect in our home aquariums thrive at a depth of 15 to 70 feet below waters surface. At those depths your primary color temps are going to be blues and violets. So in choosing a lighting option using a DIY LED lighting system, you will need to figure in the color spectrum your specific livestock will require. Typically a majority of blues and violets adding whites only for viewing pleasures. Adding reds, oranges, and yellows can stimulate growth in some but brown others. So I suggest being cautious adding too many reds oranges and yellows. I personally reccomend Blues and Violets. I cannot tell you exactly what will be best for you, Only you know your system and livestock. In determaning your spectrum (kelvin) and penetration (lux) you should have no problem building a fantastic Lighting option. I hope that i have helped answer your question, if you have any others, please dont hesitate to ask.

 

[stephnjeph]

By the way, the convertions formentioned are for heat flux intensity. There is no true way to convet light intensity to a unit of electricity. The conversions used above are very general and commonly used in the aquarium industry for obtaining a general idea of what your LUX might be at certain points of height using differant variables. There is a more complex algorithmin figuring an approximate Lux but I assumed most would not be able to use the equation properly.

 

[stephnjeph]

I am terrible at spelling by the way....

 

[greydmv]

Stephn- This makes alot of sense to me now. I appreciate you taking the time to share your knowledge which is helping me design my own DYI LED set up.

 

[Blake11rebel]

I feel like I have a better feel for my tanks lighting needs now from reading here and doing my own research. I added a purple+ t5 to hopefully bring back some of the reds and purples that have faded or morphed. I am now considering moving some of my acans to where there shaded a bit better than they are now. But poor acclimation played no part Im fairly certain.