Bubble Coral Receeding
 

I have had a large bubble coral for a year that has done well. About a month ago it stopped opening and it has slowly shrunk to a quarter of the size. Now I can see it has started to recede. I used to feed it once a week or so and then I stopped for the last few months. I have started again to feed it mysis shrimp but it had not helped. I have a 90 gallon with T5 lighting, 6 bulbs. It is placed at the bottom of the tank in a low flow area. It was near a frogspawn and I thought maybe it got stung so I moved it but nothing has changed. My parameters are all good and the only other thing that has changed in my tank is that I started adding iodine because my cleaner shrimp were losing their antennas. I stopped for over a week and it didn't help. All my other corals are thriving. Any suggestions to nurse it back to health?
Leanne

Id stop dosing and keep with the feeding, they do like low/indirect light and lower flow.... give it some time and see if it will bounce back...