First and foremost make sure that you may indeed have them, before ANY experimentation. Secondly, if you do; there is nothing known and/or scientifically documented at present time to alleviate this problem other than manual removal of ALL montipora specie and wait it out. The life span if that particular nudi im unfamiliar with, nor if their eggs can lay dorment or not. I hear some people waiting 6 months before trying montis again. Some claim success by isolation and constant monitoring and manual removal with a soft bristle tooth brush, although again nothing that has ever been claimed is an absolute definitive way to cure or alleviate them through any form of documented scientific procedure, basically no proof.
There are many other beginner sps though
The only reason I mentioned a pest is the fact that the cap in whole does not appear discolored but is pretty orange right up to the outter edge. Get a dark bowl with a couple cups of your tank water and place the cap and look CLOSELY at every centimeter, moreso along the out edge of the living tissue and in all nooks and crannies. If you still cannot see anything and have a spare clean toothbrush, ever so lightly graze the underside AND along the upperside where the dead and living tissue meet. If you dont notice anything by then nore left in the dark bowl, nudis may very well not be your problem and can go back to plan A
Other hardy SPS to try are various prostrata's, milli's,(the hairy looking acros), admired by experts and beginners alike green slimer (A. yongei), pocillopora's, stylophora's to name a few, all except the acros will not succumb to pests if introduced. All though Im not too sure on exactly what red bugs eat sounds as if their pallet is broadening from acros. A few people on the forums are claiming that there eating there LPS too? Is that right anyone?? I never had them, so ignorance is still bliss at the moment
-Justin
Then you have light intensities, too much can cause brown or bleached, to little can cause bleaching as well.
