i feed mine every now and then but it grows fine either way,once every week or two ill target feed mysis to any corals that will accept it.
i would move it to another location and see if that helps.
mine does it from time to time as most lps do, if it stays like this for more than a couple days or starts to melt then you may have an issue.
should really be testing for alk,cal,mg though if you want to raise corals
cheers