aquarium equipment question

When discussing plant lighting wattage, are we talking actual bulb wattage or the flourescent to incandescant conversion wattage? say 4 watts per gallon,, thats a helluva lot of flourescent tubes at 17 watts each, but they equal something like 60watts each tube

The actual bulb wattage. With plants it is best to use a fluorescent bulb

Compact flourescent, t5s, and LEDs all have more efficient packages. You get more light for less watts. That standard 4w/gallon only applies to the old school flourecent lights. High out t5s divide # by 3. Compact flourescent divide by about 2.5. Just my observation on plants under new light upgrades and no formula from another site. The most efficient LEDs I haven't baught yet since they cost so damn much. Hqi hallides awsome too if you have the coin since you don't need huge reflectors for the huge bulbs on earlier halide setups.
That is the whole advantage of the new fixtures...way more light for less electricity...and in a smaller space
lilydog