Same here, I've had a pink birdnest that was doing well and grew very large. Then one day had some white showing then it infected the entire nest. Before I knew it about 90% died but luckily I cut a small frag off and placed it in another tank. The bird nest made a recovery and was able to put back into the tank and it took off. I've noticed in my experience, the thinner the branches of an SPS, the more difficult they are to bring back from whiting out. Again this is just my experience.