What fish or inhabitants do you have in there that would nip anything? also what is your alkalinity at?
sorry I just tested KH and the right value is 10.9 now after 1hr of lights offim not to sure if the fish will go after polpys but possibly the butterflyfish. watch it over night maybey, im not to sure it seems that the polpys are being eaten or the tissue is burning off and the polpys burned as well but if it was burning it happen from the tips or the base mainly. hopefully a fish expert can chime in.
Im using the Salifert KH/Alk Test.huh what kind of test kit are you using? also can you track the kh to see what the swing is? usually when its alk burn it starts at the tippy top it looks like you had a old dead piece of the coral on the bottom left. did you dip the coral when you got it?
I also thought of that but I never saw the Pyramid Butterflyfish near it the only fishe that is always nipping the live rock and goes near it sometimes is the Blackspot angelfish but I never saw it touching any coral. I also thought of the Golden wrasse if the acro has any pest that I cant see.Looks to me like it is being nipped at
yeah its not alk other then i could think of would be flatworms maybey, give the sps in a revive dip before you put it in its painless and easy and very effective and check any spot thats not tissue for yellow eggs.
it looks like its being nipped, although the bottom part of the coral is dead the one spot im looking at looks like right on the poly hole there is no tissue, which means a crab shrimp fish pulled the tissue off. Dont get worried or anything i was just saying that because i saw a dead spot. if the dead spot had aefw then the eggs would survive a dip and thats mainly how they get into peoples tanks. A dip may be good now i think it disinfects the coral and also helps it to heal.