it doesn't have to run 24/7, but it can. you can use a 6500K (daylight temperature) bulb from home depot, and that will grow it just fine.
the rub, if there is a rub and i'm not saying that there is, is to stick as close to the spectrum green plants like which is your 6500K. it will still grow fine under other types of lighting, but ones closest to that color temp should produce the best results.
aside from normal light bulbs there are also a wide array of LEDs that meet this requirement as well. if you want to get fancy there are plenty of fixtures for freshwater planted tanks that should do an excellent job.