it can b done, theoretically...
if you can find or make a parabolic reflector that focuses all 72watts of light on like a 1-2 inch strip such a feeding trough or planter box, then have the bulbs 1-2 inches off the water, and choose 1 daylight bulb, and the other 50/50, and have them on 12 hours a day, it should be possible.
definitely something you could post that would be interesting...