Timanator, sorry to hear this. It's amazing how some things thrive and some do great for years and then they just tank on you. I'm very big on keeping logs and documenting everything. But to be honest, most likely it was nothing you did per se at all. With so many polyps on the market from so many different regions, it is nearly impossible to have a huge system which thrives without some mortality unfortunately. Finding the right balance of all parameters, lighting etc to adequately keep every polyp happy takes time. Once my tank is dialed in just right, I try not to change anything, even then, sooner or later, it's going to happen, DEATH. "Even though you're fed up....keep your head up" my friend.
Mucho Reef