Pests or disease to Acans?

[100gallonreefer]

Over the past 3 months I have lost 3 acans to unknown causes. My acros, montipora, zoas, and other lps all look fine. All remaining Acans look great. Usually the acans is closed up and then starts to show tissue recession and before you know it coral skeleton starts to show and it's done. Parameters are salinity .026,Ph 7.8-8.0,alk 8, cal 420-440,no3 .5, po4 .06. These values fluctuate very little daily. My question is:
Are there any pests of acans or are there any diseases that afflict them?
Thanks

 

[justinm]

I had this issue with my acans when my NO4 was too low. Raise your NO4 a bit and see if that helps. I keep mine around 5ppm.

 

[DSC reef]

Any shrimp in the tank? Any time acans showed stress in the tank for me was due to a parameter swing or nutrients being to low.