Light levels

[Owen Stubbs]

I have another thread going on my 10g setup. One component of that discussion (thanks to all who continue to respond to that) is about lighting.

Something confuses me here relative to lights. At the moment, I have your garden variety 15 watt fluorescent tank hood. I continue to study light requirements for plants, and they are always stated in watts per gallon.

Isn't that considerably off base? An incandescent "light bulb" emits a considerably different amount of "lumens" (level of light) than the same wattage (energy used) of fluorescent.

Just for example, let's take a fairly standard light in your house. An incandescent "bulb" rated at 100 watts would produce approximately 1500-1600 lumens of "light". However, a compact fluorescent can achieve the same amount of lumens at roughly 1/4 of that wattage. Metal halide, sodium, etc... there are many types of light, and there is the additional variable of frequency/wavelength, usually measured in degrees Kelvin.

So when I see these recommendations based on watts per gallon, is there a standard? Are these recommendations based on a specific form of generation (ie, incandescent, fluorescent, etc)???

[cocoa_pleco]

its 5 watts per gallon i think

[Chrona]

I have another thread going on my 10g setup. One component of that discussion (thanks to all who continue to respond to that) is about lighting.

Something confuses me here relative to lights. At the moment, I have your garden variety 15 watt fluorescent tank hood. I continue to study light requirements for plants, and they are always stated in watts per gallon.

Isn't that considerably off base? An incandescent "light bulb" emits a considerably different amount of "lumens" (level of light) than the same wattage (energy used) of fluorescent.

Just for example, let's take a fairly standard light in your house. An incandescent "bulb" rated at 100 watts would produce approximately 1500-1600 lumens of "light". However, a compact fluorescent can achieve the same amount of lumens at roughly 1/4 of that wattage. Metal halide, sodium, etc... there are many types of light, and there is the additional variable of frequency/wavelength, usually measured in degrees Kelvin.

So when I see these recommendations based on watts per gallon, is there a standard? Are these recommendations based on a specific form of generation (ie, incandescent, fluorescent, etc)???

Watt per gallon is based off of normal fluorescent lighting (T-8 bulb diameter) Compact flourescents and T-5 is slightly more efficient, T-12's slightly less efficient, and incandescents much less efficient. In general, you need 4x as much incandescent wattage to achieve the same lumens as T-8 flourescent. Even then, you need to deal with the crappy spectrum put out by incandescents as they tend to be on the lower end of the color range.

Take a look at the lighting section on my post here. It's fairly complete

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