<a href=showthread.php?s=&postid=8294212#post8294212 target=_blank>Originally posted</a> by Sk8r
I've noted something with plate coral in general: they seem to respond negatively to phosphate. I had phosphate way higher than was showing, and as I raised both alkalinity and calcium to a higher level, as recommended by the forum, my plate nosedived, lost its ability to eat, and just hung on, with some tissue erosion. After one negative experience I blamed on Phosban, I decided to try it again, and stuck with it this time. Now the phosphate level is dropping, and the plate is suddenly showing an ability to hang onto food and feed itself from other than the light alone, even though part of its mouth is eroded and algified. I have a scarlet hermit that periodically gets up on it and cleans away at that algae clump, which is a far more delicate operator than I could ever be, and in short, this coral is showing signs of coming back from this combination of circumstances.
The lethals [perhaps] were a combination of high phosphate in the background, bound, with high alk and cal.
The solution was Phosban taking the phosphate out. I wait to see whether or not it will save this coral and enable it to recover missing tissue.