Hi guys I need some help my chailce and Favia coral are receding from the edges. I just ran an ATI test and almost everything was decent my Iodine was 40.37 a little low and my Fluorine was really low at 0.30mg and zinc was non detectable. I did a big water change and my basic numbers look like this alkalinity 7.4. Calcium 400. Magnesium 1200 nitrate is 9 and my phosphate fluctuates between 0.13 and 0.05 my ph has always been low due to AC always on its about 7.8. All my sps are doing well it's just my sps especially my chailce. I have had a few high end mushrooms detach also. I have a 90 gallon with good flow and I have 3 xr5 and 6 that I run at max 80% intensity. I also have a kalk reactor and I use All For Reef. I posted a few pics of chailces that are receiving from the outside in. Anyone have any ideas? I also use Brightwell trace once a week

