Favia health problems

[TerraVlog]

Hi, I had a Favia coral for about a year, it was growing nicely but then suddenly my KH dropped from 8 to 5. I slowly raised it back up, and I didn’t notice any changes because the KH both dropped and rose gradually (I ran out of KH solution and didn’t notice it falling). The only thing that changed is that the Favia (shown in the photo) faded in some spots, and a corner of it died off, where algae has now grown. The damage appeared overnight and hasn’t gotten better or worse since. The coral still extends its polyps in the evening as usual, but I’m wondering whether that KH drop caused its health problems or if maybe a fish damaged it? Also, should I be worried and do something about it, or just leave it and let it recover on its own? The KH drop happened about a month ago.

 

[Science/G]

That alkalinity drop is probably the reason. Stability is vital. A comeback is possible, maybe a little feeding to help it recover from the bleaching. Maybe a little less light for a bit also.