whats the difference between all the T5 bulbs

I went to a web site and they had like 10 at least different T5 bulbs If im trying to grow some budd about 10-12 plans what do i need?

T5's are said to be around 2.8 times as efficient as HID. A static 400w HID would probably grow 8 plants decently. I'd say around four 54w 4 foot bulbs, making a 2x4 grid might work(20k lumens), 8 would be even better. You'll need good reflectors too. 8 bulb fixtures would probably be around 300 dollars but they do produce 40k lumens and very high PAR ratings, and are very cool running. The 8 bulb 4 foot set-ups I've seen are around 48"x 26"x 3".

Apparently they're pretty popular with (large) aquarium owners who want to grow big coral(penetrates water several feet still retaining high PAR, so it'd probably penetrate a canopy). But I've heard most have reflectors which focus most of the light downward. And they should be kept pretty close.