# 5000k vs 6500k CFL



## PatriotP (Aug 13, 2013)

Whats going to be the difference as far as plants are concerned with these two? i can get 4 of the 5000k cheaper than 3 of the 6500k but wasnt sure on plant difference and cant seem to find much online as far as what it does to plants!

Thanks!


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## Darkblade48 (Jan 4, 2008)

No real difference; plants will be fine with either bulb.

In the end, use whatever is more visually appealing to yourself (or in this case, whatever is cheaper).


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## flight50 (Apr 17, 2012)

5k is considered as morning light. 6.5k is considered noon-ish light. A bit more intensity


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## jpappy789 (Jul 28, 2013)

I've had no issues with either...unless you're able to get spectral readouts (very unlikely with standard CFLs) to see where the exact peaks are then the only known difference is how it appears to your eyes.


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## tetra73 (Aug 2, 2011)

5000k is more warmer....I like 6500k. It renders the color more accurately. It can be a bit washout.


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## xxUnRaTeDxxRkOxx (Jul 12, 2011)

flight50 said:


> 5k is considered as morning light. 6.5k is considered noon-ish light. A bit more intensity


Actually 5000k is closer to afternoon sunlight, morning light is actually between 2000k-3500k.


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## xmas_one (Feb 5, 2010)

Get the 6500. If you really want to get all crazy about it you'll find out nothing anywho.


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## OVT (Nov 29, 2011)

Strangely enough, lower K CFLs produce a tiny bit more PAR.

v2


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## jpappy789 (Jul 28, 2013)

OVT said:


> Strangely enough, lower K CFLs produce a tiny bit more PAR.
> 
> v2


Interesting, what's the rationale? Better reds? Or just something that's been measured?


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## OVT (Nov 29, 2011)

Measured, there is an older post in a sticky under Lighting comparing PAR of CFLs. Gotta hunt for it.

v2


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## sdbrewer (May 17, 2012)

What are their wattage's and what type of fixture will you be putting them in?


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## aquariumplantsplus (Aug 31, 2013)

I used to use the 6500k ge barnd bulbs all the time on planted tanks but now I cant fing them anywhere!? I bought some 5000k today at wallymart where I used to buy the 6500 k but that's was 10 years ago so I see they haven't got the 6500k anymore?


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## PatriotP (Aug 13, 2013)

Went with the 5000k! Thanks!


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## Lornek8 (Jul 3, 2013)

aquariumplantsplus said:


> I used to use the 6500k ge barnd bulbs all the time on planted tanks but now I cant fing them anywhere!? I bought some 5000k today at wallymart where I used to buy the 6500 k but that's was 10 years ago so I see they haven't got the 6500k anymore?



I just bought a twin pack of 15w 6500k last Saturday night a Wal-Mart.


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## aquariumplantsplus (Aug 31, 2013)

Lornek8 said:


> I just bought a twin pack of 15w 6500k last Saturday night a Wal-Mart.


 
what brand are they? maybe the walmarts here dont sell them anymore I haven't seen them here in years so I figure ill have to order them online from walmart most likely


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## Lornek8 (Jul 3, 2013)

aquariumplantsplus said:


> what brand are they? maybe the walmarts here dont sell them anymore I haven't seen them here in years so I figure ill have to order them online from walmart most likely


GE bulbs.


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## i4x4nMore (Mar 31, 2008)

Hi, +1 on most of the thoughts here. Color temperature is a highly gimmicky aspect of CFLs and LEDs.... You can only truly talk about color temperature with continuous spectrum sources, which CFLs and LEDs are not. As far as the plants are concerned, they will utilize light across most of the visual spectrum; some more efficiently than others, but the whole spectrum just the same. 

Personally, I like the look of 4100K CCT (correlated color temp), it has a warm and "cozy" feel about it. But I strongly confirm that with CFLs, you won't see growth differences between 3200, 4100, 5000, 6500, or 10000k. And there may only be slight PAR differences between them. 

Go for what makes your tank look best, brings out the colors in an attractive way, and compliments your room environment. If your room is softly lit with warm incandescence, then use 3200-4000K. If you use 6500-10000K, then your tank will look harshly blue against the room lighting of warm incandescence.

But don't over-stress the importance of "color temperature". Maybe if people want to get more scientific about how certain light frequencies may or may not affect reproduction or the nutrient transport mechanisms in aquatic plants, for example, then there might be warranted discussion and reasearch. But I guarantee that 99% would lose interest real fast. 

Don't be fooled by marketing or mis-information. For general growth in hobby tanks, I would support the idea that CT does not matter within the realm of common lighting.


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## i4x4nMore (Mar 31, 2008)

CFLs and PAR, from sticky:
http://www.plantedtank.net/forums/showpost.php?p=837592&postcount=21

Tom Barr's tank that shows how he mixes several fluorescent sources together:
http://www.plantedtank.net/forums/showpost.php?p=4150114&postcount=1961

Red plants lit with red light will look really red! Same logic applies for green plants, when lit by a "typical" fluorescent bulb which has a huge spike around green in its spectrum. Fluorescent bulb makers do this because the color green appears brighter to human eyes, i.e. more lumens. 

If you can't have true full spectrum lighting, then don't be afraid to mix and match to fill out the spectrum, to achieve the best color for your display tank.


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