Based only on the information you provided, I agree with BioCube14. I would bet a ton it is the ebay bulbs. You didn't mention getting say a Phoenix 14k bulbs off Ebay which would be different. I am suspecting you attempted to "save" money with cheaper bulbs, but if you have already invested a ton of money in hardware and coral, why skimp on one of the most important things. Buy some Phoenix 14K bulbs and watch what happens to your corals!

Lee