That kind of light is way to small and dim for any type of coral tank
Seriously, if it were a fish only tank even the fish would be asking for flashlights

Just kidding
Unfortunately, Lighting is one of the most
important and most
expensive single items in a reef tank. If you plan on keeping any light hungry corals you will need to buy about 8 t-5 fluorescents bulbs or if you want, a combination of metal halides and compact fluorescents.
If you are only going to keep corals that need just a little light, you might be able to get away with two four foot long aqualight deluxe fixtures
http://www.esuweb.com/cardfile.asp?I...lationship=284
Here is a picture of a combination metal halide and blue compact fluorescent fixture.
http://www.esuweb.com/cardfile.asp?I...lationship=313
The longest fixture this maufacturer makes is 6 foot. So you would have to find a way to hang it because your tank is 8 foot long. Or you could buy two four footers and hang them end to end.
I would do a lot of research before making a purchase. Look at other peoples tanks if you can and ask questions.
Jim