Finding my Kelvin Temperature?

[kimberfromwindb]

Help! I've been reading everything under the sun about preferred lighting for optimal plant growth, but I cannot find the Kelvin rating for the bulbs I have in my tank!? Anywhere....even on the manufactures' website--if anyone has any idea, please let me know! I have a Marineland Eclipse 2 Filter/Hood which comes with (2) 15W Fluorescent lights, but after 2 months, my plant growth has been ridiculously slow. Because I am not content with leaving things alone...I went and bought (1) True Actinic blue light today and replaced one of the original lights with that, but am now reading this will probably cause algae. I'm lost--anyone know what the Kelvin temp is on these Eclipse lights?:help:

[kimberfromwindb]

Hee hee...I will answer my own question-in case anyone else needs this information--the bulbs are 5000K each....so a total of 10000k. I'm thinking I can afford to keep one of those and keep the actinic as well....any thoughts??

[ThePBM]

actinic is for saltwater.
kelvin color temp doesn't add up. 2 bulbs at 5000k means you have 5000k light.

[livingword26]

Agreed the Actinic is not good for plants. 6700k - 10000k tubes would be best. What size is your tank, that hood will fit on 3 different sizes

[Joergen.Schoppe]

what about 20'000k? Isn't that closer to natural light?
But I also read they are for salt water, but his doesn't make sense to me... can anyone explain?
Are still looking for the best option for planted tanks (tubes!)

[livingword26]

what about 20'000k? Isn't that closer to natural light?
But I also read they are for salt water, but his doesn't make sense to me... can anyone explain?
Are still looking for the best option for planted tanks (tubes!)

I'm not an expert, but if you type in 20000k on an internet search, all the bulbs you come up with are advertised for saltwater tanks.

[Joergen.Schoppe]

Yes, I realized the same. But I wonder why recommended for saltwater only. What is the reason behind it? Logically the range of light is perfect for greens, but, no, they recommend it for salt water. Why?

[ThePBM]

because it's not perfect for greens and it's actually suited to corals?

[Mystix212]

Saltwater Reefs- 20,000K.
Freshwater Plants - 6,700K.

Plants require a different kelvin rating for optimum plant growth, this same rule applies for corals as they need a stronger, more intense light output.

[jones57742]

Hee hee...I will answer my own question-in case anyone else needs this information--the bulbs are 5000K each....so a total of 10000k. I'm thinking I can afford to keep one of those and keep the actinic as well....any thoughts??

One
I appreciate you finding the K rating of the incandescent bulbs in an Eclipse Aquarium.
I now know why the plants in my two 5G hex's grow very slowly.

Two
As set forth in previous posts, summing of the Kelvin rating of two bulbs is inappropriate (While this assertion is not completely accurate it is very, very close to being true).
"All that is going on here" is increased wattage but your plants are still receiving 5000K lighting.

Three
You know the saying about opinions but IMHO the blue actinic bulb may be beneficial with your freshwater aquarium.
The blue light accelerates the production of chlorophyll by the plants.
I have two 7100K bulbs in my lighting system.

Four
Please refer to
http://en.wikipedia.org/wiki/Black_body
for several charts which depict K and the associated color of visible light.

TR

[echoofformless]

Natural sunlight goes through a whole range of color temperatures depending on the time of day, the time of year, the latitudinal location, the weather, and the surroundings.

In other words say it's noon in Manhattan at midsummer on an overcast day. The color temperature of the light will be very high. One because of the clouds filtering out a lot of the lower spectra like reds, oranges and yellows. Two because the higher the sun gets in the sky, the less atmosphere there is between you and the sun to filter out the higher spectra like blues and violets. Three because the buildings are often light colored and highly reflective - enhancing the natural color rather than absorbing and changing it.

Now picture blue skies on midwinter at sunset on a tropical island. Lots of reds, oranges and yellows being absorbed by a canopy of palm trees. Getting the idea?


Plants benefit from almost all of the different spectra that the sun provides. Not to mention each individual plant has specific preferences.

The reason why 5000-7000k are the "plant" bulbs is because these are the ones which are closest to the overall average of daylight temperatures while also being pleasing to the eye. Think of it like how supposed community aquariums are classically meant to be at around a neutral pH.

But to complicate things even more, consider the fact that plants like to have peaks at certain key ranges of the spectrum - and the kelvin rating of a bulb only indicates the overall color of the light it produces. In other words two bulbs rated at 6700k may be very different when their spectrum is analyzed, with peaks and valleys in certain areas. Some of those areas are more important than others. A bulb with strong peaks in the red and blue will be more beneficial to your plants than one which has weak ones.

[livingword26]

One
Three
You know the saying about opinions but IMHO the blue actinic bulb may be beneficial with your freshwater aquarium.
The blue light accelerates the production of chlorophyll by the plants.
I have two 7100K bulbs in my lighting system.



Interesting, I have never heard that. A 7100k bulb may or may not have a lot of blue. What kind of bulb are you using, and are there any links that describe the beneficial aspects of the actinic for plants?

[Star_Rider]

I always tell em..it isn't about the K rating..it's about the spectrum .

;)

[jones57742]

I always tell em..it isn't about the K rating..it's about the spectrum.
star_rider:

I am just noting and not being argumentative here but:

1) I originally "just flat could not understand" why bulbs were not rated via wave length instead of K;

2) after getting back into my quantum mechanics books (has been 32 years since one of them had been opened) and research on the internet I achieved what I believe to be an understanding;

3) The light spectrum emitted by a bulb is not normally distributed about a given frequency but is distributed in general accordance with black body radiation;
http://en.wikipedia.org/wiki/Normal_distribution
http://en.wikipedia.org/wiki/Black_body


A 7100k bulb may or may not have a lot of blue.
A 7100K bulb, by definition, does emit blue light as observed by our eyes.
(I have two (one each in my PCs)).

What kind of bulb are you using
My current tank lighting is 300W of MH and two PC's which yield 260W.

Mh - 1063
http://www.marinedepot.com/ps_AquariumPage~PageAlias~lighting_metal_halide_cu rrent_usa_sunpod_powerpaq_hqi_lamp_lunar_light.htm l

PC - CU01013
http://www.marinedepot.com/ps_AquariumPage~PageAlias~lighting_powercompact_co mpact-fluorescent_current-usa_satellite_sunpaq_fixtures.html


Interesting, I have never heard that.
, and are there any links that describe the beneficial aspects of the actinic for plants?

Blue light is responsible primarily for vegetative (leaf) growth
http://extension.oregonstate.edu/mg/botany/light.html

Blue light responses: Many plant responses are regulated by blue light, including phototropism, stomatal opnening and chlorophyll synthesis. The last step of chlorophyll synthesis requires high levels of blue light. The other blue light responses are triggered by lower levels of blue light
http://www.mobot.org/jwcross/duckweed/phytochrome.htm


livingword26:

These are not the pages which I reviewed in my original research but I am old and cannot find these pages (which are much more descriptive).

TR

[livingword26]

star_rider:

I am just noting and not being argumentative here but:

1) I originally "just flat could not understand" why bulbs were not rated via wave length instead of K;

2) after getting back into my quantum mechanics books (has been 32 years since one of them had been opened) and research on the internet I achieved what I believe to be an understanding;

3) The light spectrum emitted by a bulb is not normally distributed about a given frequency but is distributed in general accordance with black body radiation;
http://en.wikipedia.org/wiki/Normal_distribution
http://en.wikipedia.org/wiki/Black_body



A 7100K bulb, by definition, does emit blue light as observed by our eyes.
(I have two (one each in my PCs)).


My current tank lighting is 300W of MH and two PC's which yield 260W.

Mh - 1063
http://www.marinedepot.com/ps_AquariumPage~PageAlias~lighting_metal_halide_cu rrent_usa_sunpod_powerpaq_hqi_lamp_lunar_light.htm l

PC - CU01013
http://www.marinedepot.com/ps_AquariumPage~PageAlias~lighting_powercompact_co mpact-fluorescent_current-usa_satellite_sunpaq_fixtures.html




Blue light is responsible primarily for vegetative (leaf) growth
http://extension.oregonstate.edu/mg/botany/light.html

Blue light responses: Many plant responses are regulated by blue light, including phototropism, stomatal opnening and chlorophyll synthesis. The last step of chlorophyll synthesis requires high levels of blue light. The other blue light responses are triggered by lower levels of blue light
http://www.mobot.org/jwcross/duckweed/phytochrome.htm


livingword26:

These are not the pages which I reviewed in my original research but I am old and cannot find these pages (which are much more descriptive).

TR

Thanks for all your time. I will research your links.

[loaches r cool]

Actinics could be somewhat useful. If you look at the action spectrum of photosynthesis youll see peaks in the blue range. For example here are some graphs showing the absorption spectrum:

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/pigment.gifhttp://www.emc.maricopa.edu/faculty/farabee/BIOBK/absorspect.gif from http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html

Now look at actinic it looks like:
http://www.theaquariumsolution.com/files/imagecache/yourcontentnode_mainimage/files/products/Pure%20Actinic2.jpg
This happens to be a bulb for sale on marine depot http://www.marinedepot.com/ps_viewItem~idProduct~GL2143~tab~1.html

You can see that the spectrum does indeed fall within the action spectrum for photosynthesis. But its lacking over 50% of the spectrum offered by daylight bulbs, or actually lacking closer to 80 or 90% perhaps. So they are not a good choice alone, or if your trying to make the most efficient setup for growing plants. But all actinics are not equal. Some actinics peak at shorter wavelengths yet, with a lot of energy in the 300's of nm. In that case most of that energy is not useful at all, photosynthesis drops of sharply less than 400nm.

The reason that actinic is sold for marine tanks is because light in deep marine water is mostly blue. So for those situations, the high Kelvin and actinic light is the natural light. For freshwater plants, that are often in just a couple feet of water, the spectrum of light is pretty much the same as we see it, usually in the 5,500-6,000K range.

K values are often overrated and also very inaccurate. Often times a 3500K bulb or a 15,000K bulb will work as well or better than the common 6500K choice. So basically dont worry to much about it. Get what you like, half of the choice is aesthetics. Its the wattage thats going to be of more importance for the most part.

[livingword26]

I thought this might add to the discussion. Here is the color analasys for 4 coralife t-5 bulbs

First the Actinic
http://akamai.edeal.com/images/catalog3684/folder24579/img3040067.jpg

Next the 6700k
http://akamai.edeal.com/images/catalog3684/folder24579/img3040068.jpg

Next the 10000k
http://akamai.edeal.com/images/catalog3684/folder24579/img3040066.jpg

And finally their full spectrum (That comes in the freshwater combo light)
http://akamai.edeal.com/images/catalog3684/folder24579/img3040065.jpg

[livingword26]

What would be interesting is if someone could find an analysis chart of what kind of spectrum algae prefers.

[Reefscape]

Saltwater Reefs- 20,000K.
Freshwater Plants - 6,700K.

Plants require a different kelvin rating for optimum plant growth, this same rule applies for corals as they need a stronger, more intense light output.

Actually, for optimal coral growth, 6500k is the ideal "k" to choose...

Thanks

Niko

[loaches r cool]

What would be interesting is if someone could find an analysis chart of what kind of spectrum algae prefers.

Algae uses photosynthesis... meaning it will be about the same. The difference being that algae I believe has more accessory pigments so it can utilize a broader spectrum of light. I believe I read somewhere that cyano can utilize green wavelengths which few plants can. Algae and plants are very similar. Think of it like weeds in your garden. The weeds and veggies use the same light and same nutrients. Weeds are just more opportunistic and when the conditions arent ideal and veggies arent doing well the weeds sure still can be... same thing with algae.

[livingword26]

From link in earlier post

http://extension.oregonstate.edu/mg/botany/light.html

Light quality refers to the color (wavelength) of light. Sunlight supplies the complete range of wavelengths and can be broken up by a prism into bands of red, orange, yellow, green, blue, indigo, and violet.

Blue and red light, which plants absorb, have the greatest effect on plant growth. Blue light is responsible primarily for vegetative (leaf) growth. Red light, when combined with blue light, encourages flowering. Plants look green to us because they reflect, rather than absorb, green light.

Knowing which light source to use is important for manipulating plant growth. For example, fluorescent (cool white) light is high in the blue wavelength. It encourages leafy growth and is excellent for starting seedlings. Incandescent light is high in the red or orange range, but generally produces too much heat to be a valuable light source for plants. Fluorescent grow-lights attempt to imitate sunlight with a mixture of red and blue wavelengths, but they are costly and generally no better than regular fluorescent lights.


Algae uses photosynthesis... meaning it will be about the same. The difference being that algae I believe has more accessory pigments so it can utilize a broader spectrum of light. I believe I read somewhere that cyano can utilize green wavelengths which few plants can. Algae and plants are very similar. Think of it like weeds in your garden. The weeds and veggies use the same light and same nutrients. Weeds are just more opportunistic and when the conditions arent ideal and veggies arent doing well the weeds sure still can be... same thing with algae.

If all of the above information is true, then the 6700k bulbs (Shown above) that I have been using (which put off a distinct green hue) are actually more prone to grow algae than the Full Spectrum, 10000k, and Actinic bulbs I listed above. 6700k bulb are touted as being on of the best plant bulbs, it is beginning to appear that science contradicts that?

[jones57742]

If all of the above information is true, then the 6700k bulbs (Shown above) that I have been using (which put off a distinct green hue) are actually more prone to grow algae than the Full Spectrum, 10000k, and Actinic bulbs I listed above. 6700k bulb are touted as being on of the best plant bulbs, it is beginning to appear that science contradicts that?

livingword26:

Nope.

1) the 6700K bulbs are what I call "grow light" bulbs in that the spectrum which they emit is close to sunlight.

2) I do not understand "the distinct green hue business". Mine just appeared as a very dull whitish light (which is the reason that these bulbs are in the garage now).

3) Prior to MH I only had two 10000K and two 7100K bulbs.

4) IMHO please forget your concept of the "algae business" as, once again IMHO, our aquarium plants are much more efficient in their utilization of light and nutrients than are algaes.


Tristan:

It is my turn now!

Did you say that the two 7100K bulbs which I have in my PC's are beneficial for my plants??

Also, and as usual you have really done your homework, some of the literature suggests that red light may also be beneficial to plants.
What is your opinion?

TR

[ansbfish]

http://www.current-usa.com/sunpaq.html

I was going to replace my 420/460nm actinic w/ 6700k/10000k daylights, but now I'm not so sure, and I already ordered the bulbs...

Thanks a lot loaches r cool :nilly:

[livingword26]

livingword26:

Nope.

1) the 6700K bulbs are what I call "grow light" bulbs in that the spectrum which they emit is close to sunlight.

2) I do not understand "the distinct green hue business". Mine just appeared as a very dull whitish light (which is the reason that these bulbs are in the garage now).

TR

Kelvin rating, from brand to brand, does not always emit the exact same light spectrum. The coralife 6700k t-5 tubes that I posted about earlier have a very green hue. I have all 4 of those bulbs and the hue is clear. The full spectrum has pinkish hue, the 10000k is white, perhaps faintly blue, The 6700k is green, and the Actinic is of course blue.

[loaches r cool]

If all of the above information is true, then the 6700k bulbs (Shown above) that I have been using (which put off a distinct green hue) are actually more prone to grow algae than the Full Spectrum, 10000k, and Actinic bulbs I listed above. 6700k bulb are touted as being on of the best plant bulbs, it is beginning to appear that science contradicts that?

Well actually you could look at it that way. Most plant grow bulbs have very little green at all... I have had a couple, last one being the Aqua-Flora Plus (a T6 bulb by Quantum) and it is very purplish and emits most of its energy in the reds and blues (hence purple). But as far as promoting algae with green light... like I already said just about anything that is good for plants is good for algae too anyhow, so just focus on promoting the plants. And green light makes are plants look so nice.

Human eyes are great at automatically adjusting to various lights... often times you dont realize the color of a bulb as anything but 'white' until its next to another bulb. But yes, many very popular daylight spectrum bulb have a heavy amount of green, which makes them look brighter to our eyes (lux, lumens). For example here are two 6500K bulbs I have that definitely have a green cast:

http://tristan.homelinux.net/fish/forum/lights.JPG
3rd bulb in from left is Philips Daylight Deluxe 6500K

http://tristan.homelinux.net/fish/240g/lights5_400.JPG (http://tristan.homelinux.net/fish/240g/lights5_800.JPG)
GE Starcoat 6500K T5HO on top, definitely green. However the Giesemann 6000K midday bulb (2nd up from bottom) has no greenish cast but is a tad yellower.

Note the apparent colors are enhanced by a fast shutter speed of the camera. To the naked eye they are much brighter and more whitish.

I am not promoting the use of actinics. Just trying to say they arent some evil thing that will make your plants dissolve and algae prosper (unless of course you dont provide plenty of other light, nutrients, co2, etc). They only put out a very small portion of light usefull for plants. Tom Barr says it best I think, plants like a lot of reds with a little blue. ;)

[jmhart]

Agreed the Actinic is not good for plants.


I'm agreeing with this, but I just wanted to state this more clearly. Actinic is not beneficial to plants. It won't harm them, but assuming limited space for bulbs, it's a waste of space for plants.

A lot of people do leave these on there cause they like the color. Assuming you have enough of ~6700K light, actinic won't "hurt" your plants.