CFL Question Regarding Wattage

Trying to understand whether using CFL would cover the bases as far as watts needed per gallon in a planted tank. Examples that I have seen are from Home Depot, "The EcoSmart 27-Watt (100W) Daylight CFL Light Bulb". Would this be actual 100 watts for my tank (which would be sufficient for a 25 gal tank)? The specs does not indicate the kelvin, but the employee had indicated that it would be the same as 6500K (daylight).

Thanks for helping me in understanding.

I use them in a couple of my tanks and my understanding is that you go by the actual wattage (27w) when calculating how much you need.


Heres some info:

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