# Fluorescent Bulbs



## nick007x (Sep 9, 2005)

Aquarium lighting can be confusing, so I put this together. A primer for lights:

*Length*: Measured in inches

*Diameter*: Check the tube for the diameter code:
T12&#8230;1-1/2" T8&#8230;...1"
T10&#8230;1-1/4" T5&#8230;...5/8"

*Temperature (Color)*: The Kelvin temperature of a fluorescent bulb indicates whether it brings out the cool, blue end of the color spectrum or the red, warm end of the spectrum.

Warm 
* Color temperature 3000 - 4000 degrees Kelvin
* Red light is essential for plant growth, so a planted aquarium reguires either this type or a full spectrum bulb. However, along with high nutrients, red light also causes algea growth.

Cool
* Color temperature 4000 - 5000 degrees Kelvin
* Clean, white light for general use

Daylight 
* Color temperature +6000 degrees Kelvin
* Bright light with true color rendering

At around 6700 K the high noon sun spectrum is reproduced. At color tempertures around 18,000 K, fish colors can intensified (especially red and blue) and plant growth stimulated.

As Kelvin temps go past 18,000+ the light becomes a powerful cool blue. This is the type of light is used primarily for reef lighting in marine tanks, which also often require blue actinic, high output (HO), or very high output (VHO) bulbs.

To achieve intense reef light in large tanks, Halide lighting is used. It is more expensive than fluorescent lights but provides very intense light. Best suited for plants and invertebrates.

Most normal fluorescent bulbs are "Triphosphor" lamps, which have an internal formulation of phosphors which enhance greens and reds. Triphosphor lamps have varying degrees of light production in the following portions of the spectrum: violet/blue, blue-green, green-yellow and orange-red. Most Compact Fluorescent lamps presently on the market are tri-phosphor lamps (except for 'blue' and 'actinic' lamps).

I realize that's a lot of color information, so here's some important things to remember:

Warmer color tones highlight red and orange pigments.
Cooler color tones accentuate white, blue and bronze colors.
Bright, neutral light simulate natural light conditions.
A bulb with a high color temperature (K) must be a full spectrum light if you want to grow plants, meaning the bulb must have plant growth promoting (red) wavelengths, in addition to the other wavelengths it produces. The overall effect of these lights are generally bright, true color, and do not look more tinted one color or another.

*Color-rendering Index (CRI)*: Refers to how well the light from the bulb reflects true colors.

The CRI scale tops out at 100, the equivalent to natural sunlight or soft white incandescent bulbs. The CRI for fluorescent bulbs typically ranges from 50 for a basic bulb to 90 for a plant and aquarium bulb.

*Light Output*: Measured in lumens. A 15 watt flourescent bulb provides 900 lumens of light. The wattage refers to how much energy is needed to power the light. Wattage is not a measure of light output. For example, if you wanted to produce 900 lumens with a regular household incandescent bulb, you would need a 60 watt incandescent bulb compared to the 15 watt flourescent bulb. This is one of the reasons why they produce less heat. Some other watt to lumen figures:

18 watt (1100 lumens)
25 watt (1750 lumens)

High light output is useful in promoting plant growth.

Fluorescent bulbs lose approximately 50% of their lighting effectiveness within one year, resulting in a distorted spectrum, inefficient plant and coral growth and less intense fish colors. Most bulbs will emit light for a span of 6,000 - 10,000 hours however, their effectiveness begins to wear off after approximately 5,000 hours of usage. Plan on replacing yours after 6 to 8 months.

Hope that helped.

Cheers,
Nick


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## nick007x (Sep 9, 2005)

I'm sorry, can someone move this to the Equiptment Forum please? Thanks-


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## harrykaa (Jan 10, 2005)

nick007x said:


> ... However, along with high nutrients, red light also causes algea growth...
> ... Some other watt to lumen figures:
> 18 watt (1100 lumens)
> 25 watt (1750 lumens)


Hi nick007x,

That is a nice piece in information.
However, I would like add some more info which is particularly important to aquarists.

*A) wavelengths*
Actually the most efficient "lights" to algae are:
1) deep blue (wíth a small portion of UV-light), this is under 400 nm
2) yellow-green light.

One must remember that algae have evolved in this planet much earlier than macrophytes (higher plants). At the time they evolved sunlight was different form what it is now. This is the reason algae use up slightly different portion of light than the macrophytes so. However there are exceptions. Some algae living in deep waters (red algae, Rhodophyta) do not need red nor yellow light at all, they do well in blue light, which penetrates deepest into the water.

*B) lumens*

All different types of fluorescent bulbs emit different amounts of light energy, which can then be measured in lumens. A general rule, however, is that daylight bulbs are most efficient. Also some new "comfort" type bulbs (which emit warm light very near to incandescent bulbs) are very efficient. For example 36W bright sunlight and comfort type bulbs emit about 3250 lumens. This is quite much compared to new aqua or plant growth types, which emit about 2200-2500 lumens (36W).
So the wattage (intake power) does not tell how efficient the bulb is for the plants. Plus a good reflector can increase 200-300 % the light energy that is directed downwards to the tank from the bulb.
This is also why I do not pay very much attention to the watt per gallon rules. It is totally dependant on the type of bulb and fixture you are using: power, color temperature, wavelengths, reflectors ...

Regards,


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## nick007x (Sep 9, 2005)

Thanks Harry, excellent addition-- true on both parts. With the watts to lumens, I only meant that as an example to illustrate fluorescent lights' efficiency vs. incandescent.

As far as the light/algea, I was kind of oversimplifying it. You are completely correct in that blue light does indeed cause algea growth, just in a different way I think than the red light I was talking about.

Tell me if you do or do not agree: The green color in plants is comprised of slightler higher amounts of yellow light than blue, so some blue light is used, however that is the plant's method of "knowing" how much light it is recieving. So you could say a plant grows bigger from red light, and it "knows" how big to make it's leaves based off of blue light, because how much blue component it is recieving is a good indicator of the total light available (in the full spectrum of normal sunlight). However, if an aquarium has _only_ red light, plants will grow at a more rapid pace, because without blue light, it thinks it is recieving NO light. I was assuming this was true for algea as well, being it's also a plant. I may be wrong though, do you agree or no?

ooohhhh............deep water (red) algea. i just read your post again, apparently too fast initially. yes, completely--just as most plants use no green light because they are green and therefore reflect green light, red algea reflects (uses no) red light.


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## EZmoney (May 13, 2004)

great thread, guys!

get it pinned!!!!!


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## Husky_Jim (May 26, 2003)

nick007x said:


> I'm sorry, can someone move this to the Equiptment Forum please? Thanks-


As requested,moved to equipment forum.

NIce post!


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## Fresh2salt (Jul 16, 2004)

great info to know guys thanks


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## Trystan (Jan 2, 2006)

really good posts guys.


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## dopper3 (Sep 5, 2004)

From what I can understand... Is it best to buy some daylight bulbs (Those with the highest CRI and Kelvin combination) or is it best to have a red bulb and a blue bulb (assuming I have two bulbs)... Also, this might sound really stupid... but when I look at my bulbs, I can physically tell that one is very reddish while the other is very blueish, is this the proper combination? I'm asking because I currently have 2.6wpg (2 20w bulbs, one blue, one red, each with high kelvins, proper chelated iron levels, CO2 injection and I still have algae problems... Admittedly I have high phosphate levels and am currently working on bringing that under control, but is my lighting system good?


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