# kelvins



## zombie (Apr 14, 2004)

are the kelvins the colour?

the higher the k's the more blue they produce?

is any thing below 6700 arse?

would i be ok with 620w with the bulbs being 3100 k?

thanx in advance for the help need this to be perfect(until i change again :laugh: )


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## harrykaa (Jan 10, 2005)

zombie said:


> are the kelvins the colour?
> the higher the k's the more blue they produce?
> is any thing below 6700 arse?
> would i be ok with 620w with the bulbs being 3100 k?


Hi Zombie,

Here is my recent thread on the subject:

The 10.000K fluorescent bulb is very commonly sold in Finnish lfs and in common stores for aquarium purposes. These are labelled as FLORA, FLORALUX, TROPICAL etc. and from the brands like SERA, OSRAM, SYLVANIA etc.

The light they emit is claimed to promoto photosynthesis. It has greater amount of blue and red light compared to green.
It has been shown that green chlorophyl absorbs red and blue light much more than green light. This has led to a conclusion that a 10.000K light is best for photosynthesis.

BUT. Few things have been forgotten.
1) Plants (and waterplants as well) do have other pigments also than green chlorophyl. They have yellow and red pigments as well. These pigments need more yellow and green (red pigment) or green (yellow pigment) than blue or red to manage photosynthesis.
2) Take a look at power output of a 10.000K fluorescent bulb. Lets say the input (power consumption) is 36W (which is a 4' or 120cm bulb).
In OSRAM
the basic-type (white 4.500K) output is 2.800 lumen;
the flora-type (10.000K) output is 2.000 lumen;
the comfort-type (warm 6.000K) output 3.350 lumen.
It is very easy to see that the red-blue color has been done by only reducing the green light. The bulb does not emit more red or blue light than the basic-type or comfort-type bulb.

As a whole, the reason to use a wide spectrum light (near white, 5000K-6000K) is very simple one. The plants on earth and in water have evolved during hundreds of millions of years to get best use from the sunlight (5.600K).

If one claims that his plants grow better with a 10.000K bulb, he also states that his plants qrow better than those in nature with sunlight!

BTW. A fluorescent bulb basically emits three main types (wavelengths) of light:
red, green and blue (RGB light).
A human eye sees the light as white when all three are emitted similar to daylight.
A green leaf is green (as a human sees it) because it does not absorb the green light as well as other wavelengths and thus it emits green more. But it does not emit back all the green light!

PS. I have tried using 10.000K lights many times as a primary light source in aquarium. Each time especially green brush algae takes advantage of this, but the higher plants seems to slow down compared to wide spectrum lights. I believe that one should try 10.000K lights but only when combined with wide spectrum lights. And it is better to use only the latter ones.

Regards,


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## Husky_Jim (May 26, 2003)

I suggest you try Power Compact bulbs.They are better,less energy and you can find them in all wanted kelvins and lumens.


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## zombie (Apr 14, 2004)

this is the thing been on fulhams site if i get some company to order them ill be fine they are 80w hi-lumen t5 cct(K) 6400 each bulb is about 5900 lumens and tey are 4 pin cfl 2g11 base do you think these will be ok


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## zombie (Apr 14, 2004)

been on osram uk and they do 80w 6000 lumen but no mention about colour apart from cool white i think it was the dulux l 840 is this ok


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## harrykaa (Jan 10, 2005)

zombie said:


> been on osram uk and they do 80w 6000 lumen but no mention about colour apart from cool white i think it was the dulux l 840 is this ok


Hi Zombie,

Yes I figured it. It seems that manufacturers (OSRAM here) use different types of bulbs in different marketing areas. My experience is from Finland/EU.

Anyway, bulbs called "natural white" and "warm white" have been previously sold here. If you have found cool white, it simply means that the bulb emits less red light (warmer means more red and cooler means more blue).

That does not sound exactly good. Warm white imitates sun light and that is fine for plants and fine if you want natural undistorted colors. Using cool white will emphasize blue color. The one I use at the moment is "comfort" and it emphasizes a bit red color. That bulb imitates incandescent bulb (common glow lamp) color.

Regards,


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## zombie (Apr 14, 2004)

so your saying get a warm bulb. I see they do this 1 aswel.I thought cool white would be ok as this is the type of bulb i use for vegging weed


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## harrykaa (Jan 10, 2005)

zombie said:


> so your saying get a warm bulb. I see they do this 1 aswel.I thought cool white would be ok as this is the type of bulb i use for vegging weed


Hi Zombie,

Yes exactly.

I noticed you are dealing with compact bulbs (like OSRAM DULUX). These are lamps that have been created to overtake incandescent bulbs. They are compact, but the lumen power (actual output) is not as good as with tubular fluorescent bulbs.

See two 36W OSRAM "comfort" (827) pruduce 6.700 lm and a single OSRAM DULUX 80W "warm white" (830) produces 6.000 lm.
*This means that tubular bulbs produce about 24 % more light.*

The color temperature (K) of OSRAM "comfort" is the same as OSRAM DULUX "interna" and the color code is 827.

Regards,


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## zombie (Apr 14, 2004)

the thing is i have a big ass tank needs 640w just for 2.7wpg this is why im going for the 22.5" 80w so then i should go for the warm white from osram


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## harrykaa (Jan 10, 2005)

zombie said:


> the thing is i have a big ass tank needs 640w just for 2.7wpg this is why im going for the 22.5" 80w so then i should go for the warm white from osram


Hi Zombie,

OK, that sounds fine.

regards,


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## zombie (Apr 14, 2004)

thanx for this


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## Husky_Jim (May 26, 2003)

i am now testing several different power compact tubes and i will post the results as soon as i have made a conclusion.

Just for the record i use warm with very good results....


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## harrykaa (Jan 10, 2005)

husky_jim said:


> i am now testing several different power compact tubes and i will post the results as soon as i have made a conclusion.
> 
> Just for the record i use warm with very good results....


Hi there husky_jim,

can you please include (if you already haven't done so) the "interna" (OSRAM) color (code 827) into your test.
I use it myself (tubular version, "comfort") and it seems to be very effective.
Actually the change from the combination of "natural white" (4.500K) and "flora" (10.000K) to "comfort" caused an enormous boost for the algae.

Regards,


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## spree_rider (Mar 20, 2004)

you can use half cool white and half warm white tubes to get an inbetween colour, this is what professional growers (growing something other than aquatic plants) in my area seem to get the best results for the price.


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