# 4100K vs 6500K



## Kathyy (Feb 22, 2010)

It will grow plants just fine. The color may look too yellow to your eye is all.

My betta tank originally had a low K bulb over it and the fish looked purple. When I found a 6500K bulb he turned blue with some red on his fins. Beautiful either way I guess.


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## BBradbury (Nov 8, 2010)

*Your Light*



ovenmit331 said:


> Quick question. Ordered a replacement 13w CF bulb on Amazon. Description says 6500K. Bulb arrives and it's 4100K. Is that useful to me (in regards to a planted tank) AT ALL?


Hello oven...

You can use it, but it's not in the right color spectrum. The 6500K is closer to natural daylight, so would be preferable.

B


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## jeffkrol (Jun 5, 2013)

BBradbury said:


> Hello oven...
> 
> You can use it, but it's not in the right color spectrum. The 6500K is closer to natural daylight, so would be preferable.
> 
> B


Not really, 6500k is not magic..
someday this urban legend will die..


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## ngrubich (Nov 29, 2011)

jeffkrol said:


> Not really, 6500k is not magic..
> someday this urban legend will die..


+1. 

If anyone else is interested, here's a link:
http://info.gtilite.com/the-d50-daylight-myth/#.VPjjVMZ5dKo


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## Bushkill (Feb 15, 2012)

I'll simplify it for ya,

Use the one you like.


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## jeffkrol (Jun 5, 2013)

Bushkill said:


> Use the one you like.


best advise.. 

BTW: In case your wondering one of the reasons it bugs me is this 6500k thing is NOT the best spectrum for LED's YET people believed it was, and when it was performing "sub standard" or didn't "look right" well you get the picture..


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## burr740 (Feb 19, 2014)

I have a 20H with CFL bulbs. Not all brands will look the same, but I generally prefer 5000K over 6500K, based strictly on color rendition. 

Plants grow just fine.


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## jeffkrol (Jun 5, 2013)

ngrubich said:


> +1.
> 
> If anyone else is interested, here's a link:
> http://info.gtilite.com/the-d50-daylight-myth/#.VPjjVMZ5dKo


Just a bit on 6500k. Just a rough comparison.. :









3000k and 4000k leds:









A 6500k high CRI flourescent for comparison:









http://www.carnivorousplants.org/howto/SoilsWater/Lighting.php


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## adamfish (Feb 3, 2015)

The Kelvin rating is what we see, the wavelength is what the plant sees.

Not all Kelvin ratings with result in the same wavelength.


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## ovenmit331 (Mar 27, 2007)

Thanks guys. I'll keep it and see what it looks like (although I'm colorblind so I probably wouldn't notice the difference between 2500K and 10000K)


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## Steve001 (Feb 26, 2011)

ovenmit331 said:


> Quick question. Ordered a replacement 13w CF bulb on Amazon. Description says 6500K. Bulb arrives and it's 4100K. Is that useful to me (in regards to a planted tank) AT ALL?


You'd have to look at this bulbs spectral output. It may have adequate output in the blue portion of the visible spectrum, but the blue is overpowered by a higher output in the redder parts of the visible spectrum.


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