wpg?

glembke

Registered Member
Mar 12, 2006
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0
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Excuse me, im a newb, but why do you guys use watts per gallon when figuring out how much light to use for a tank? Watts doesnt have any correlation to actual light output, why not use lumens?
 
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Lumens are a measure of perceived brightness by the human eye, meaningless for plants - people see green best, exactly what plants reflect and do not use.

Watts, for standard normal output fluorescent tubes, are the best rough measure available. For other than NO tubes, it needs fudge factors.
 
joephys said:
Your right, that is the best way. Watts per gallon is usually used since most people use fluorescent lighting for their tanks. Most bulbs are usually about the same output so people just use watts per gallon because its a little easier to talk about 2 watts per gallon than 35 lumens per gallon.

I guess I can understand that. I just upgraded from 50watts of incadescent lighting, to 26watts of Compact Fluorescent lighting. So my actual wattage dropped by 50%, but the CFL's put out lighting equivalent to 120watt incadscents. More than doubling the light output.
 
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watts per gallon refers to standard flourecent. you need __ standard flourecent watts per gallon to grow ______ plant. you can't say that 26 watts of flourecent light is equal to 120 watts incandecent to the plants. because its not. i have 60 watts flourecent light on my 20g tank, and its 3 watts per gallon, but if i had 60 watts of incandecent light on my tank, the actual light output would be MUCH lower. when comparing incandecent and flourecent, THEN you must take into account lumens. incandecent puts out far fewer lumens per watt than flourecent does.
 
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