bleachimg chalice

[joe demo]

hi i have a 14 gal bio cube ,6 months sps lps corals n 2 clowns live rock my question i have a chalice coral 4 months old 3 days ago i noticed a quarter size blemish on it the the next day 3 blue leg hermits were feasting on the area to the point of white . not sure what took place . i do water change once every 7-8 days about 3 gallons.all of my other stock seams healthy and growing. lights are on about6 hours a day. i do have a zenia that has grown some and one of its branches slightly brush against the chalice . i check my perameters once a week before and after water change. they always seem ok. just my nitrate is about 5.0 before water change.phosphate0.25 or less,ph 7.8 ammonia 0.0 nitrate0.0 these perameters are before water change my concern is the5.0 nitrate so i cycle 3 gallons fairly simple to do with a small tank any suggestions thanks joe

 

[Tab28]

Not the nitrates. Chalice like many lps prefer a bit nitrates. 5.0 would not be considered high even for sps tank. The hermits were just eating off the area that was decaying. It could be too much light and it was an area that was damaged. I would dip it and put it in a low light area.