My clams are suddenly dying. Rotting away from the bottom. I have had all three for about a year with no problems what so ever. I just got back from vacation and when I left they all looked fine. when I got back (6 days later) one was almost completly gone and the other 2 are rotting away. All of my other corals and everything else living are doing great. The only thing I have changed in the last month or so has been my lighting. I went from 3-10,000k MH to 3-20,000k MH bulbs and I also have 2-VHO flourescents that are due for a replacement. Could that be my problem? PLEASE HELP!!!!!