We started with PCs then upgraded to HO T5s and now we only run MHs. With each upgrade, we noticed a big difference. I even ran some high end 3w CREE leds for a while. But to be honest, we get better growth and color from our cheap 250w 20k ebay bulbs and they last about 8 months. A single 250w MH over your 29g would be enough light to grow anything. We have a 4' cube running 4 250w MHs and a 20" cube running one 250w MH on the same sump, and we dont have any heat issues. If you ever come up this way, you're welcome to check out our set up. We've gotten better growth and color using MHs and they make more sense for us for cost efficiency. So we have to replace 5 MHs every 8 or so months for a total of about $55 with shipping. If we we're to switch to T5s it would cost much more than that.