I'll chime in, and probably confuse the issue more!
Regarding the 26W vs 100W... as far as household lighting is concerned, one of those 26W fluorescent bulbs gives off the same amount of "light" as a 100W incandescent. "Light" is an unexact/incorrect term here, because you're really talking about lumens or lux or par or some other scientific quantity of light. But sticking a bulb in a lamp, a 26W swirly gives off the same apparent light as a 100W old fashioned bulb. So I believe CaptainAhab is correct.
We're not talking "reading" light here, were comparing aquarium lighting. And when people talk about 100W of aquarium lighting, they're not talking about incandescent bulbs - they're talking about fluorescent. They're talking about the amount of "light" 100W of fluorescent lighting (or MH
) gives off. So if you're going to compare that swirly bulb with a real aquarium lighting fixture, in my opinion, you need to compare fluorescent watts to fluorescent watts - which would mean you'd use the 26W.
Regardless... I wouldn't use it.