T5's are growing macro just fine... If you're providing sufficient light, and can't get macro algae to grow, it's more than likely that you've got a nutrient deficiency of some sort. Most any light will grow macro algae. BRS has been doing all sorts of tests and videos to show which lights are the most efficient, and they're right, if your goal is to control algae growth in the display tank, you need the macro algae to out compete GHA, or whatever it is you're trying to get rid of. A high end light source, in the proper spectrum for growing macro algae is important. Still... I know many people that use cheap, low output lighting to grow macro algae, and it grows just fine... provided the nutrients it needs are available.