Influorescent... doesn't exist. A google search turns up 10 results and suggests you change the spelling to in fluorescent. You may be thinking of incandescent.
The two differ in a fundamental way, in that a fluorescent bulb (tube) involves the excitement of a gas, while the incandescent bulb involves the extreme heating of a tungsten (metal) coil.
The incandescent is not at all adviseable for tanks, as it produces a great deal of heat, does not light as well, and produces rather too much yellow light. The flourescent is adviseable, esp. the 18,000
K variety, because it provides the tank with a more sun-like light. In addition to all this, the tube fits better over a tank, and illuminates all of the water, rather than patches of it.
Hope that helps. Sorry if it's commonsensical.
