I picked up a 29g yesterday on CL, and it came with a fixture for a single 24" T8 tube. Is it going to be possible to get decent growth from any T8 bulb in this set up, or do I have to upgrade? I know I could stick with REALLY low light plants, but I'd rather not be so limited. Low tech tank (I might use a few root tabs, and perhaps excel, but nothing serious, and no CO2). Roughly 15" from light to sand.