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Any one know an incandescant 15 watt bulb that is 6500k or close to that? I need the compact screw in kinds.

Thanks in advance.

You mean the 6500k 15w compact flourescent spiral "pig tail" bulbs which are not incandescent but are designed to replace incandescent bulbs.

(FWIW incandescent bulbs are basically glowing wires the put out a whole range of frequescies or k values).

Wall mart at least the last time I checked has GE 6500k bulbs for like 2 for $8. They are in a blue bubble pack and say "6500" vertically down the side. Seems to work fine for me.


my .02
 

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You can use CFL bulbs, they should fit right in to an incandescent socket. I got the Sylvania brand from Home Depot, they work like a charm.
 

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(FWIW incandescent bulbs are basically glowing wires the put out a whole range of frequescies or k values).
Most lights emit a range of frequencies. Kelvin temperature does not refer to the nanometer wave spectrum emitted from the light emits but the over all color of the light. Most common household incandescent emit a low kelvin temperature in the 2,700-4,000 range. Which, IMO anyway, looks terrible over an aquarium since its a ugly yellow light.
 

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Most lights emit a range of frequencies. Kelvin temperature does not refer to the nanometer wave spectrum emitted from the light emits but the over all color of the light. Most common household incandescent emit a low kelvin temperature in the 2,700-4,000 range. Which, IMO anyway, looks terrible over an aquarium since its a ugly yellow light.

FWIW and from my memory the K values refers to the light given out by a black body heated to that temperature. Therefore the k value is very much tied to the wave length of the light. Or at least the light spectrum anyway.


owww heck I looked it up. :lol:

from: http://en.wikipedia.org/wiki/Kelvin

http://en.wikipedia.org/wiki/Kelvin said:
Colour temperature
Main article: http://en.wikipedia.org/wiki/Colour_temperature
See also: Stefan–Boltzmann constant
The kelvin is often used in the measure of the colour temperature of light sources. Colour temperature is based upon the principle that a black body radiator emits light whose colour depends on the temperature of the radiator. Black bodies with temperatures below about 4000 K appear reddish whereas those above about 7500 K appear bluish. Colour temperature is important in the fields of image projection and photography where a colour temperature of approximately 5600 K is required to match "daylight" film emulsions. In astronomy, the stellar classification of stars and their place on the Hertzsprung–Russell diagram are based, in part, upon their surface temperature, known as effective temperature. The photosphere of the Sun, for instance, has an effective temperature of 5778 K.
 

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Discussion Starter #8
I noticed that cfl 15w is equivilent to a 60w incadescant bulb... A little to bright for my 10 gallon. Are all flourescant lights this bright? Are the tubes this bright?

Also, I want to replace two 15w incandescant, so a 15w compact flourescant is probally not going to work (based on what I've seen). How many watts should I get?

Thanks for all the replies!
 

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it will work, just a lot more visible light than the true incandecent bulb


I've seen 40 watt equivalent ones (9-10 watt) in 6500K, I wouldn't expect two of those to be excessive, but it all depends on what you are hoping to accomplish, live plants? otherwise Kelvin rating/spectral distribution is largely irrelevant
 

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Discussion Starter #10
I'm looking at two 13 watt (60 watt equivelent) for my 10 gallon. So your saying its the same amount of light just more in visible light right? If so this should be good right?
 

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the CFLs will produce more visible light, they will be brighter

if considering bulbs of both types that use about the same amount of energy (not the 'equivalent to' number for the CFL), most of that energy is converted into nonvisible heat in the incadescent, where a much higher percentage is converted to visible light in the CFL- as much as would be produced from an incandescent using 4x the amount of energy (15 watt CFL equivalent in visible light output to 60 watt incandescent)

if you think it may be too bright, go for the lowest watt CFL you can find, i've seen ones that are 5 watts (30 watt equivalent), but you may be limited in choice of K rating, which is important if live plants are planned
 

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FWIW and from my memory the K values refers to the light given out by a black body heated to that temperature. Therefore the k value is very much tied to the wave length of the light. Or at least the light spectrum anyway.


owww heck I looked it up. :lol:

from: Kelvin - Wikipedia, the free encyclopedia
Yes it is tied to the light spectrum, but only very loosely. It is very common for two different brand bulbs with the same kelvin rating to have very different light spectra. Since the kelvin temp is an over all measure of light. This is especially true with the higher kelvin temps as there are lots of ways to make a bright white bulb.
 

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Discussion Starter #13 (Edited)
the CFLs will produce more visible light, they will be brighter

if considering bulbs of both types that use about the same amount of energy (not the 'equivalent to' number for the CFL), most of that energy is converted into nonvisible heat in the incadescent, where a much higher percentage is converted to visible light in the CFL- as much as would be produced from an incandescent using 4x the amount of energy (15 watt CFL equivalent in visible light output to 60 watt incandescent)

if you think it may be too bright, go for the lowest watt CFL you can find, i've seen ones that are 5 watts (30 watt equivalent), but you may be limited in choice of K rating, which is important if live plants are planned
I do have plants so that might be tricky... My thought process is that if 3w per gallon is hight light than a two 13w (60w equivelent) will be 12w per gallon. Figured that high light would stress out my fish and make my low light java fern leaves turn transparent.

Edit: Stumbled upon someone saying that the replacement rating should be disregarded and that it is only melt so the fixure won't melt... My hood takes up to 25w bulbs, but that doesn't make any sense because that would require less than 5w cfl.

I think at this point I will just go with the 6500k 13w cfl I found.

Thanks for all the help guys!
 

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I noticed that cfl 15w is equivilent to a 60w incadescant bulb... A little to bright for my 10 gallon. Are all flourescant lights this bright? Are the tubes this bright?

Also, I want to replace two 15w incandescant, so a 15w compact flourescant is probally not going to work (based on what I've seen). How many watts should I get?

Thanks for all the replies!

Wht watts per gallon measure is for flouescent not incandescent watts. 15w over a 10 would be fine.

even better 2 7-10w to spread the lightout.

my .02
 

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yes, the watt per gallon measure is only relevant when talking about fluorescent lighting and really only certain types of fluorescent lights

because of the different efficiencies of the different types of lighting, it becomes difficult to compare light output by energy consumption

I agree with beaslbob and would try to find a bit lower wattage CFLs 2 10 watt ones would be good

Regarding the side conversation; Kelvin when applied to incandescence and black body radiation absolutely describes the specific spectral distribution of the light source. The relative amounts of the different spectra will then result in a particular color appearance when perceived by human vision.

Kelvin when applied to fluorescent lighting is the 'correlated color temperature'. It describes the appearance of the light relative to a black body source, e.g. a fluorescent 6500K light will have the same appearance as a black body source at 6500 K (around 11250 degrees F). Light sources of differing spectral distribution can result in the same color appearance (and have the same K rating), but the level of variation is not unlimited, it has to be in the same ballpark, which is why K is useful in estimating spectral distribution and is sometimes the only guide available.
 

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I use 10W CFLs in my 10 gallon. Anything more was an algae farm, even the two 10W are a bit on the high side for that so my light period is under 8 hours. The 10W are 40W equivalents. I got them at Walmart for pretty cheap (GE brand).
 
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