# 6,700K vs 10,000K in planted tanks



## OVT (Aug 26, 2010)

It caught my attention that a lot of people are using 10,000K lights in their planted tanks.
Let's say we take 2 bulbs from the same manufacturer (Coralife), one 6,700K and another 10,000K (I could only find their respective spectrum info on the packaging, not on the web).

Visual appearance of the tank aside, any significant effect on plans one vs the other?

(Sorry if this subject has already been beaten to death ..)


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## Newt (Apr 1, 2004)

All Coralife bulbs emit large amounts of green light. There are much better bulbs out there.

The kelvin of a bulb only matters to you in that what color of light you like to view your tank under. People in europe are using bulbs more in the 4100 to 6000K. I have found it is best to mix/blend the lighting. I find that a white light suits me best.


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## Left C (Jun 14, 2005)

Years ago, using T12 bulbs, there were comparisons of "white" bulbs with a slight blue cast (around 10,000K) and "white" bulbs with a slight red cast (around 3 to 4000K). One produced "leggy" growth and the other produced "squatty" growth. I can't remember which was which, now. Maybe Newt or someone can go into more detail. The information is probably on "The Krib" somewhere.


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## Newt (Apr 1, 2004)

If you want to optimize plant leaf development (blue light) and *stem elongation and color (red light)* you need light in both the blue and red spectra for photosynthesis. You need a mix of blue and red for your plants, and green for you (brightness as perceived by humans). If your lighting looks extremely bright and your plants seem ultra-green, it means that you have lighting that outputs strongly in the green spectrum.

These growth patterns are not a result of the kelvin color temp of the bulb it is from what light the bulb is producing throughout the visible spectrum (spectral output). The combination of all those colors and spikes of colors blend to make the bulb's kelvin temp estimation. The plants 'see' the colors and spikes not the blend of colors.


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## singolz (Oct 27, 2011)

from walstads book, her studies indicate that green and yellow lights actually gave more beneficial growth rather than the reds and blues commonly perceived. 


Sent from my iPhone using Tapatalk


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## Newt (Apr 1, 2004)

A lot of Diana's theories have been disputed. If a plant is green it is reflecting that light NOT absorbing it to create photosynthesis.

University studies presented in the Journal of Plant Physiology show plants utilize red and blue light most efficiently. Other colors can contribute to photosynthesis but not efficiently.


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## Raihana (Dec 7, 2011)

Anyone have an opinion on the Power Compact Bulbs offered by marine Depot?


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## old 97 (Jul 25, 2011)

OVT said:


> Visual appearance of the tank aside, any significant effect on plans one vs the other?
> 
> ..)


Would a PAR sensor contribute facts?

http://pcp.oxfordjournals.org/content/50/4/684.full


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## ecotanker (Jun 12, 2009)

Thanks man! A very interesting article. It gives some support that plants can adapt to whatever color light is available, even green, but will use the light more efficient with several colors. 

Definitely worth reading just to find that plants, some of them anyway, use green light as efficiently as red.


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## Left C (Jun 14, 2005)

Raihana said:


> Anyone have an opinion on the Power Compact Bulbs offered by marine Depot?


This is a broad question. What wattage and what pin configuration are you looking for?

MarineDepot's PC's: http://www.marinedepot.com/lighting_powercompact_compact-fluorescent_bulbs-ap.html

Many of their PC's are the Current-USA brand. Their 6700K, 10,000K and dual daylight 6700K/10,000K bulbs are very good. I've used them over the years and I have no complaints. Their dual daylight bulbs are my favorites from these choices.

There is an 8800K PC bulb called Colorquest. It was the Custom Sealife brand. Custom Sealife went out of business and reopened down the street with the Current-USA brand. Anyway, if you can find these bulbs and you can use a square pin arrangement in either 65w or 96w, grab them up. These are excellent bulbs. Some places have them at closeout prices. I picked up a couple of 65w bulbs about a year ago really cheap. These are great looking bulbs. I like them better than 6700K or 10,000K bulbs. The natural colors seem to brighten up with these bulbs. https://www.google.com/search?q=880...s=org.mozilla:en-US:official&client=firefox-a

GE makes a 9325K 55w straight pin bulb that does a good job when mixed with other bulbs. It puts out a pinkish color and it really enhances your red plants and fish. By itself, it is too pink for my taste. http://www.atlantalightbulbs.com/ecart/10Expand.asp?ProductCode=F55BX.AR.FSGE


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