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Jeff Lefkowitz
Regular Member
Username: jeffedl

Post Number: 174
Registered: 01-2005
Posted on Wednesday, February 15, 2006 - 08:10 pm:       

I called marineland to see what they recommended to increase the light output on my Eclipses. They suggested looking for specialty bulbs up to 20 watts, with higher Kelvins. I went to look at Bulbs on some web sites and just got overwhelmed at the types, and equally underwhelmed about the support information.

So my questions:
1. What is Kelvin, and how much of it do I want/need for my situations (see below)
2. The Eclipse specs on Dr. Foster and Smith say that the replacements for them are T-8. What does this T factor mean, and does it mean I must use bulbs that are T-8 or can I can use other Ts.
3. For the tank with one 18" bulb, am I better with a full spectrum, or specialized? Why? For the tank that has 2 bulbs (24") should I get two different types, and what would the best split be?

The two tanks in question are a 10 gallon with an 18" bulb that has fish and java moss, java fern, and anacharis (sickly from not enough light). The 29 gal has 2 24" bulbs and has the same plants. I also have a 12g that uses a compact bulb, and that tank has an amazon sword that won't grow taller than 2" so I'd like to put it in a place with more light.

Can anyone share wisdom with me?
"Peter, the fish did not bite you through the glass"
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Regular Member
Username: gomezaddams

Post Number: 577
Registered: 05-2005
Posted on Wednesday, February 15, 2006 - 08:58 pm:       

About the t factor the t-12 are the big shoplight 1.5" diameter bulbs t-8 are 1" diameter and are the ones you find in standard aquarium hoods.the t-5 are really narrow bulbs.The narrower the bulb the higher the light output for fluro.
Waiting will fill
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Ancient Member
Username: rasaqua

Post Number: 3731
Registered: 01-2003
Posted on Wednesday, February 15, 2006 - 11:01 pm:       


In response to your first question:

Kelvin color temperatures attributed to different types of lights are correlated based on visible colors matching a standard black body, and are not the actual temperature at which the gas or phosphors inside the tube burn at.

Larry got question number two

In response to question number three:

Lumens is another important factor in determining type of lighting you may want to achieve. The more lumens per watt, the better.

A lumen is a unit of measurement of light. It is a way of measuring how much light gets to what you want to light. A foot-candle is how bright the light is one foot away from the source. A lumen is equal to one foot-candle falling on one square foot of area.

Lets move away from lumens for now. This is another alternative to go with in search of both biologically and aesthetically favorable light tubes. Look for "K" and "CRI"

K, as you know represents color temperature. This indicates the color appearance of a light source. CRI, (color rendering index), indicates the color appearance of the objects lit by that source.

How close a light source comes to a given standard in rendering colors is expressed as a percentage of 100. CRI of 100 is sunlight. Full spectrum light source tubes would be between 5000 and 7000 K.

What would this mean to you? You'll be fine with a full spectrum light source and a CRI of 90 and above.

Plants take in and use light in both the red and blue end of the spectrum. They also use it in the green, yellow, and orange. However, we see colors better in that spectrum also. So, thus is recommended a full spectrum tube that represents something to enjoy for us and the plants.

"For every difficult question, there is an answer that is clear and simple and wrong."
(George Bernard Shaw)
Badman's Tropical Fish - Archives * Equipment & DIY * Lighting, Bulbs, and T-Factor       

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