The florescent tubes don't usually put out many lumens, by nature. If you want a LOT of lumens, use high intensity discharge lamps (HIDs) like metal halide (the best), mercury vapor, or sodium vapor lamps. The mercury vapor and sodium vapor lamps tend to emit more in one end of the spectrum and little in the other (mercury = too much blue/violet, sodium vapor = too much yellow/red). Metal halide lamps produce an extremely bright blue-white light that is amazing for plant growth. However, these lamps are not for small spaces; they emit as much heat as they do light, and produce way too much light for a ten-gallon. They are also sooooo expensive!!!
By the way, something to consider is that lux (luminous flux: lumens/meters^2) is just as important as lumens. A smaller space will need less lumens than a larger one.