blue lights for coral

[sansouci01]

Are blue lights just as important as white for coral.....

 

[bribo12]

No the blue lights also known as actinic lighting is more for aesthetics and causes corals colors to pop more. Light in the 10,000-20,000 kelvin range is what most corals need to grow. 10,000 kelvin will be better growth but more of a white look while 20,000 kelvin is a blue color and slower growth. the 20k however makes the corals pop more. A lot of people do not like a strictly white tank so they use actinic bulbs or blue leds to make the tank look more blue. Corals zooxanthellae (photosynthetic algae in their flesh) may use a tiny bit of this for photosynthesis but most of the light being used is in the 10k range.

 

[johnsonw2]

I thought the blue was as important or more important than the whites

 

[Grizz]

I thought the blue was as important or more important than the whites

+1 The blue light waves are better for the coral. All though they do use the full spectrum of light rays. Iv'e seen better growth with just blue than with just white.

 

[Mebbid]

I was using a 10000k and 6500k bulb for a little while due to my actinic bulb dying and it made my corals all horrendous looking. While the color they had didn't "pop" very well they actually changed color to brown.

I will add that sunlight is at about 6500k and corals in shallow areas don't get the blue filtering of the light. I am not really sure that it matters what the color spectrum is, corals should use the available light either way.

 

[MaiTank]

Corals need PAR not so much color. It is the correct PAR value that creates growth and health along with proper nutrients.

 

[doaz]

What are some good par levels?

Kevin Baker

 

[Ingy]

PAR is a general name for the light transmitted in the 'ENTIRE' range of photosynthetic life. That is to say PAR light works for plants as well as corals. But, plants and corals need very different spectrums of light. Plants like lower K (warmer) light in the longer wavelength of visible light, while corals preffer the higher K range (cooler) of light in the shorter wavelength. But, both those spectrums are still considered PAR light.
Chlorofyll comes in 2 general families. There are the ones used mainly by plants that absorb the 650-700nm range of light, and the other that absorb the 420-500nm range of light that corals have.
So, a high PAR value of 680nm light might just starve a coral. 450nm is about blue (actinic) light.

 

[Gregcoyote]

PAR is a general name for the light transmitted in the 'ENTIRE' range of photosynthetic life. That is to say PAR light works for plants as well as corals. But, plants and corals need very different spectrums of light. Plants like lower K (warmer) light in the longer wavelength of visible light, while corals preffer the higher K range (cooler) of light in the shorter wavelength. But, both those spectrums are still considered PAR light. Chlorofyll comes in 2 general families. There are the ones used mainly by plants that absorb the 650-700nm range of light, and the other that absorb the 420-500nm range of light that corals have. So, a high PAR value of 680nm light might just starve a coral. 450nm is about blue (actinic) light.

You are describing PUR, or the usable radiation a coral can utilize. They are very adaptable, some live in less than a foot of water where they get the full spectrum from the sun, others live where only blue light penetrates. They can use both white light and blue light when necessary, although warmer temperatures of white light cause brown algae to dominate in some corals, that's why the color change.

When using my PAR meter, I have founds corals don't need as much light as I thought. I find soft corals can live in less than 150 PAR easily, LPS like about 200-250 PAR and my low light SPS likes 300 PAR while some high light SPS does well at 400-600 PAR. This is using LED panels.

 

[Ingy]

You are describing PUR

Yes and no. I don't want to overly complicate the issue at hand. However someone said corals need PAR and not specific colour. That is incorrect as corals need a specific range of PAR, specifically that in the blue range of light. Yes that is starting to describe PUR, but that will just confuse people.

Corals want PAR light in the 420 - 500nm range (blue-purpleish).

What would your PAR meter say if I supplied a very bright ORANGE light (680nm say). the PAR meter would read a significant PAR value if it measures all PAR light. But your coral would shrivil up and die as not enough PUR value for the specific photosynthetic bacteria. And those orange lights are very popular for growing plants.

So all that to say to the OP, PAR values are a very good indication as long as the light is designed for the application. Actinic light IS what your corals want. The white light is so WE can see all the pretty colours.

 

[bribo12]

Yes and no. I don't want to overly complicate the issue at hand. However someone said corals need PAR and not specific colour. That is incorrect as corals need a specific range of PAR, specifically that in the blue range of light. Yes that is starting to describe PUR, but that will just confuse people.

Corals want PAR light in the 420 - 500nm range (blue-purpleish).

What would your PAR meter say if I supplied a very bright ORANGE light (680nm say). the PAR meter would read a significant PAR value if it measures all PAR light. But your coral would shrivil up and die as not enough PUR value for the specific photosynthetic bacteria. And those orange lights are very popular for growing plants.

So all that to say to the OP, PAR values are a very good indication as long as the light is designed for the application. Actinic light IS what your corals want. The white light is so WE can see all the pretty colours.

I am almost positive a coral grown under a warmer light would not shrivel up and die, it would just be browner. Corals in very shallow reefs are not getting the complete blue spectrum that deepwater corals get. Yes a deepwater coral will thrive from bluer lighting but a shallow water coral will do better with a full spectrum light. Corals zooxanthellae use a wide spectrum of light not just the 420-500 nm range. Hence the reason people use warmer lights. For example, someone running 2 of the same exact fixture with different bulb colors over 2 sides of heir tank. Te side with the cooler blue color will have better color but not as fast of growth while the warmer color will have faster growth but not as great color.

 

[Gregcoyote]

That's my view as well. I have grown corals under cheap flood lights. PAR is PAR. Corals will grow under magenta lights meant for hydro farming, they just won't be as colorful. Same with blue light , but the colors pop more. You don't have to have actinic lights to grow coral. JIMO