A Favour Needed

Hi people...I want to add a floresant light to my tent to increase foilage but I don't know what tube to get. Apperantly there are two types hot and cold. At present I have one of those "black Light" (actually the light is blue but anyway...) and the plants seem to be really happy, they look great. But I want a longer tube and more importantly I want your advice. So what tube should I buy?

Maybe....('hope I'm not out of order here...) but maybe someone could post me a link (on ebay) as to the best light to use.

Many thanks in advance.

T-5's are great, I use them for clones, but they are great for supplemental lighting.

6500 K AKA Daylight, black lights don't do anything really.
http://www.htgsupply.com/Category-T5-Fluorescent.asp

Thanks for the replies guys...and thanks for the link John....

okay....I just tried to buy one (ebay uk) but was givren a choice....."warm" or "cool". Which one guys? )