Struggling to keep green slimer alive. Coral was very healthy when I got it about 3 weeks ago. First it browned a bit, then it started losing tissue. It starts to look better and then it browns and loses more tissue. Monti and birds nest seem to be doing just fine. I did have an alkalinity drop and I may have brought it back up a little too quickly. So do I attribute this as the cause and wait it out? Could it be the lighting? The piece is in a shallow tank under a kessil 160. I decreased and increased light but did not see any improvements. Is it pests? I included the other picture (sorry I forgot the name I was told) because it looks like something took a bite out of it. Tank has only two clowns and a peppermint shrimp. Tank parameters are alkalinity 9, pH 8.1, Calcium 390. Nitrates are near 0. Is it low nutrients?
Would appreciate any help.