How did this end up, still having die off? I just had the same thing happen a month ago. I think my tank is finally stabilized, just fighting the algae from the die off issues now. Only thing that survived was a Dendro, one pink zipper and half my frogspawn, which still probably wont make it. Also, how is your sand mine got pretty hard in a few places. I feel your pain about losing the corals, I'm pretty bummed probably going to stick to a more simple softie tank now.