I have an orange Monti I got at the October event. Over night it developed a bright white spot on one of its plates. It is about the size of a dime. Any thoughts? Water is perfect. T5 lights 8 hours per day. Good flow and a blow debris off of it.
You could try to move it up or down in the tank. I had one do that to me and I moved it to the lower level of the tank and it grew back over the spot in about two weeks but I caught it as soon as saw it but the spot was about the same size as yours. monti's are fairly tough IMO. Just keep your eye on it after you move it to make sure it doesn't get any worse.
I had the same thing happen and it turned out to be the dreaded Montipora eating nudibranchs. Some time after your lights have been out for an hour or more, check your monti/montis for these guys which are about the size of a grain of rice or smaller: I'm not saying that's what it is for sure, but that was just my experience. Here is some information about them: http://www.qualitymarine.com/News/Feature-Articles/The-Montipora-Eating-Nudibranch-(09/11/06)
Eww! I hope it isn't motipora eating nudibranches! I have battled those in the past. It is a very slow and painful process to eliminate them from your system. As far as size... Don't even count on them to be as big as a grain of rice. Your best bet on finding them, is to check the coral at night in the dark. That is when the nudi's come out. Look between the folds and in the corners. I hope you don't have them.
I don't see anything on it. It has progressed. The entire plate is lighter. It is only on one plate though. I am dipping it again. This will make the 3rd dip. Once when I got it, once when I noticed the first spot and today. Anything else I can do? Do I need to dip my other hard corals again?
I would break off the pieces that look healthy and reglue them, that way you isolate the healthy chunks.
I would not dip any sps that does not need it. Just because one os bleaching, has nothing to do with the others and all your doing is stressing them and I ahve never had much luck with dipping SPS. SPS can STN for a number of reasons. It is one of the hazards of having them, Acros are even worse, look at them crosseyed and they bleach. I personally have never saved one by dipping. I have saved LPS by dipping, but never SPS. The best thing to do has already been suggested and that is to cut some of the uneffected areas and hope that saves a few pieces, sometimes it works and sometimes not. If all your SPS start STNing, you have something astray in the tank that needs to be addressed in a hurry.
think I got lucky. I don't think it was nudi and the dip didn't seem to hurt it. The spot is gone and I can see some new growth. Thanks for all your help!
I can't think of any reason for the bleaching. I don't think it was too much light bc I moved it to the 90 gal and it has a much higher intensity. Maybe it was not enough light even though it was at the top of the tank