Your lighting is minimal at best for sps corals. A good rule of thumb would be 5 watts per gallon (which you are close too). This is just a general rule, other factors such as tank depth and placement of corals will also dictate lighting requirements. Deeper tank=higher wattage light, so that there is a high par rating (lower par means insufficient spectrum reaching bottom of tank). At a 24" tall, you might be ok with what you have.