Assuming all your filtration and parameters are good, I highly recommend a pair of Ecoexotic Panorama combo fixtures (blue/white) for your 30 gallon tank. I'm running two on my 40 gallon tank and I have about a dozen of coral pieces in my tank (including some SPS corals). And they are all doing excellent. I will admit though, it took a little effort to find the sweet spot for my SPSs, but once I found it I couldn't be happier. After owning them for the last 6 months, I've come up with the following Pros/Cons with these lights:
Pros:
Cheap (under $100 each).
Modular (if I get a bigger tank all I got to do is get more lights and they fit together).
They're LEDs (they are no strain on my electric bill, don't have to replace bulbs, and no need to buy a chiller since they generate almost no heat).
Powerful (like I said, I only have 2 of them in my tank and all the corals, including the ones that require intense light, are happy and thriving).
Cons:
Each one has its own power supply, so be prepared to have a bunch of power cords hanging out from your tank (although I heard its possible to link them to one AC adapter, but I haven't tried).
The light beam that they emit is kind of narrow, so finding the perfect spot for your SPSs could be tricky, depending on how you've aquascaped your live rock.
They create a hypnotic shimmering effect in the water, so its possible to lose track of time, important dates such as birthdays, anniversaries, funerals, 1st kid being born etc because you stared at your tank too long lol!