Although it is tempting to save a little money on a lighting system it is one of two areas where you should spend as much as you can possibly afford, the other being the skimmer. The fixture you are looking at which has 2x39Watt HO T-5’s has a total of 78 Watts of light. While you may be able to get some low light corals to limp along under that little amount of light, you will not get any growth or color. The color on many corals is actually a “sunscreen”, the zooxanthellae in the coral act in a way that gives the coral its color. Without adequate light, there is no need of the “sunscreen” and hence you have little to no color.
One issue you are running into is that with T5’s you are limited to 39 Watt bulbs (at the 36” size). A fixture with 4 bulbs for a 30 gallon tank which I am guessing is 36” would give you 156 total watts, still not overwhelming. A compact fluorescent 36” fixture would give you 2x96 Watts or 192 total.
TBH I would be willing to bet that over 75 percent of Reefers would buy a better light system if they had it to do over again. Lights are one of the most oft upgraded items because we just never seem to have enough! Rather than buy a fixture that will end up on the junk pile and be replaced by a fixture that truly meets your needs later, why not go all in now and buy the light that will suit your eventual needs. This is my advice for most system components. Buy the component that will adequately meet the demand down the road, not the one that barely meets the need now.
I would recommend a metal halide / compact fluorescent combo unit, with a 150 or 250 MH and 2 65 watt PC’s for a total of between 280 and 380 total watts. If you watch the forums you can pick one up used at a decent price. Alternatively, go retrofit and buy Steelheads Icecap Ballast 660-009
http://www.reeffrontiers.com/forums/showthread.php?t=55060
It is a great deal for 3 bulbs 6 endcaps and the ballast. If you have a hood that you can mount those in, then Steelheads light system is probably your best bang for the buck.
Hope that wasn’t too much info, but trust me, if you want to get into this seriously, buy the best light system you can.
Ichthys
PS My coralife 4x65 PC fixture will be for sale soon as I did not heed my own advice. I am upgrading to
http://www.reeffrontiers.com/forums/showthread.php?t=55565 which is 2x250w HQI's and 2x96w PC's.