I'm confused about light

[Just John]

Most people say that yellower/ lower K light, such as 8,000 k, is better for coral growth than higher K, such as 25,000 k. When you look at a graph showing the best colors for coral growth it is blues (and some red). Here is my question, If I take an 8,000 k light and a 25,000 k light and crank them both up to 100% blue, why is one better than the other for growth?

 

[Zer0]

Because the blue color spectrum activates the florescent tissue in coral(not all), and the daylight spectrum boosts photosynthesis in the zooxanthellae in the coral. But that’s a super simplified version of it.

 

[Just John]

Because the blue color spectrum activates the florescent tissue in coral(not all), and the daylight spectrum boosts photosynthesis in the zooxanthellae in the coral. But that’s a super simplified version of it.

Here is a generic graph I found online for the different types of chlorophyll. Chlorophyll A and B absorb in the blue to purple wavelength. So, if I set both lights to full blue and purple, or any other color (full red or full green or whatever) why is one better than the other? In short, why is a full blue 6,500 k light better than a full blue 25,000 k light for growth? (or use any color or mix of colors you want to)

 

[reefinatl]

Here is a start, keep in mind the par numbers discussed here are specific to that coral and the chlorophyll within it.

 

[Just John]

Here is a start, keep in mind the par numbers discussed here are specific to that coral and the chlorophyll within it.

To try to simplify, set each light to the same color or color mix. Why is one better or worse for growth than the other if the color settings are the same? (Edit: the video just showed up after I replied somehow, so I have not watched it yet)

 

[Zer0]

Excellent video, thank you for sharing.

Here is a start, keep in mind the par numbers discussed here are specific to that coral and the chlorophyll within it.

 

[ZoWhat]

You are confusing spectrum with kelvin.

..............................................................
Light Spectrum is a specific color of visible light. It has a specific wavelength, 380nm for violet up to 800nm for red

..............................................................

When you combine all colors of visible light, what is produced is WHITE LIGHT coming at your eyes.

As you are reading this, any white that you see is all the violets, blues, greens, yellows, oranges, reds ....all mixed together to produce WHITE light.

Sidenote: a good way to see this is to freeze-frame a white screen on your TV. Get within an inch close to the screen and you'll see specs of different blue, green, reds, the whole spectrum of light. HA!!! You thought white light was a color, but its the combo of all colors of light. (Dont hurt your eyes)

KELVIN is the color shade of WHITE LIGHT... not a specific wave length in the spectrum

When you hear "Kelvin", they are talking about the shade of WHITE light... not a specific color

Meaning a 1000K white light will be heavy on the RED wavelength spectrum but still have smaller amounts of all visible light.

20,000k will be heavy with BLUE wavelength spectrum but still have small amounts of all visible light

A 420nm wavelength spectrum will be specifically pure-BLUE and not have any other visible wavelengths

A 800nm wavelength spectrum will be specifically pure-RED not have any other visible wavelengths

 

[Just John]

You are confusing spectrum with kelvin.

Light Spectrum is a specific color of visible light. It has a specific wavelength, 380nm for violet up to 800nm for red

When you combine all colors of visible light, what is produced is WHITE LIGHT coming at your eyes.

As you are reading this, any white that you see is all the violets, blues, greens, oranges, reds all.mixed together to produce WHITE light.

KELVIN is the color temperature of WHITE LIGHT... not a specific wave length in the spectrum

Again a specific light color is a specific wavelength in the visible light spectrum

Kelvin is in terms if the color tones/temps of WHITE light that is made up of all the light spectrums

Meaning a 1000K white light will be heavy of the RED Lightwave spectrum but still have smaller amounts of all visible light.

20,000k will be heavy with BLUE Lightwave spectrum but still have small amounts of all visible light

A 420nm Lightwave spectrum will be BLUE and not have any other visible Lightwave

A 800nm Lightwave spectrum.will be REDLAND not have any other visible Lightwave

Thanks for the pictures, etc! I have a light that allows you to change the blue, red, etc. levels and the box says 25,000 k. So am I correct that they are saying the factory setting is at 25,000 k, but if I change the percent red, blue, etc. I will be manually changing the color temperature? Sorry if I sound like an idiot!

 

[Azedenkae]

You are confusing spectrum with kelvin.

Light Spectrum is a specific color of visible light. It has a specific wavelength, 380nm for violet up to 800nm for red

When you combine all colors of visible light, what is produced is WHITE LIGHT coming at your eyes.

As you are reading this, any white that you see is all the violets, blues, greens, yellows, oranges, reds ....all mixed together to produce WHITE light.

KELVIN is the color temperature of WHITE LIGHT... not a specific wave length in the spectrum

Again a specific light color is a specific wavelength in the visible light spectrum

Kelvin is in terms if the color tones/temps of WHITE light that is made up of all the light spectrums. If you hear "Kelvin", they are talking about the shade of WHITE light... not a specific color

Meaning a 1000K white light will be heavy of the RED Lightwave spectrum but still have smaller amounts of all visible light.

20,000k will be heavy with BLUE Lightwave spectrum but still have small amounts of all visible light

A 420nm Lightwave spectrum will be BLUE and not have any other visible Lightwave

A 800nm Lightwave spectrum.will be REDLAND not have any other visible Lightwave

Finally, an answer to op's question. I was confused too.

So this makes a lot of sense now. Thanks!