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Argument came up in chat..... what exactly are the important things to consider when planning the light for a planted Freshwater Tank.

Discuss.

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These may not all be the official terms, but the bits in parentheses should help clarify. Not necessarily in this order.

Power (watts)
Intensity (lumens)
Spectrum (um, spectrum)
Color temperature (Kelvin temp)
Type (fluorescent, etc)
Efficiency (both power-wise and reflector efficiency)

Probably other things as well but those are what jump to mind.

Last edited by LittleMousling at 16-Nov-2004 13:11

-Molly
Visit shelldwellers.com!

Mousling, specturm is the wavelength measurement of the colors.


Here read these;

Please read closely about the kelvin, CRI rating, and PAR, as well as the parts about the spectrum. As well, try to get an understanding of how these all work together to get the perfect conditions. Both are written in easy terms for anyone that wants to read them. The second one is very long, and very explainative, adn thourough. The second has some data at the end on some different commonly used bulbs.

http://www.drhelm.com/aquarium/lighting.html

http://www.vengers.com/faq/faq14sec41.htm

HTH.....

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There is always a bigger fish...

I know, but I didn't think it really needed further explanation. Of the five I listed, it's the most commonly understood behind watts; after all, it's something studied in every year of earth science, in physics, sometimes in biology with plants, and even in chemistry. Since everyone has taken at least a few of those at some level or other, it needs little further explanation.

-Molly
Visit shelldwellers.com!

spectrum is the measure of wave length in different coloured lights
the wave length can affect the rate of photosynthesis by allowing more or
less light being absorbed by the chlorophyll

Turns out I wasn't confused after all. While yes 5500K bulbs are good for plants they give off a really nasty color, 65/6700K bulbs are just as good and don't turn your tank funny shades that make you think you were given the wrong pair of glasses entering oz.
So Daylight 65/6700K bulbs to around 2wpg is what I'm sticking with. They're a little more pricy than the regular bulbs (in the case of screw in florescents) but as far as the color goes they're worth it.

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Intensity
Intensity
Intensity
Intensity.

I would also argue that planning the plants to match the light is a more important, and oft overlooked step, concept.

---

Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Just for some more advanced research, read this site, and check out the difference in the different K ratings on these bulbs. When looking at the pics, you can see that several of the tests were done on bulbs of the same company, and you can see the further away from 6500K, the bluer the color is. And the closer to 6500K, the yellow or more whiter the color is. At the below website, go to the right of the screen and click on the link;
"250 Watt metal Halide Testing"

http://www.cnidarianreef.com/



Last edited by ACIDRAIN at 25-Nov-2004 08:18

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There is always a bigger fish...

Fixed link above.

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There is always a bigger fish...

Hi,
Plants make use mainly of light in the red and blue
parts of the spectrum. Thus "plant lights" also have
spikes in the red and blue area.
Bulbs that are in the 4-5,000K range tend towards
pinkish to reddish light. Bulbs, as they surpass
the 10,000K range become bluish to blue in their
output. Bulbs that try to use both spikes in color
tend to give off a pinkish purple light.

In either extreme, the resultant light tends to wash
out the plants true colors. Bulbs in the 6000 to
8000K range, preferably in the 6700K range tend to
give the truest color rendering.

Check out this site:

http://www.aqua-web.org/users/saurama/index.htm

This site shows tanks that are luminated with different
bulbs. It gives vivid examples of what I'm talking about.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Frank, that site is a good one for camparison of what the bulbs will look like to our eyes, and it does show the wave length of the bulbs. But, it does not give readings of them, as in par values and such.

And the bummer is that it is all written in German.

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There is always a bigger fish...

And the bummer is that it is all written in German.

Absolutly nothing wrong with german

^_^

Nothing wrong with it at all, if you can read it. Babel, seeing as you are such a nice person, will translate those pages for me, please?

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There is always a bigger fish...