You can grow many SPS corals with your lighting but most of them will not maintain the color or grow very fast. In the case of a 15 gal tank fast growth may not be something you want anyway. Green corals tend to keep their color even under lower lighting. There are deep water Acropora corals that are also available that require less intense lighting. Montipora corals in general do very well under fluorescent lighting (PC or VHO).
HTH,
Kevin