What’s going on with my trumpet coral?

[kbnh]

This was growing and splitting up until Wednesday/Thursday, second coral not doing well since my water change on Wednesday but would that cause this? It was the same salt as I always use, I’ve even used from the same bucket.
The display side of the coral looked fine just retracted, I looked from the side and saw the degradation. Any ideas on what this may be?

 

[kbnh]

Could it be too much flow?

 

[Grootzilla]

It’s possible that a fish or invert might be picking at it

 

[AFHokie]

Have you verified parameters and did you check the new water? Even in the same bag of salt I’ve had some big inconsistencies despite mixing to the same salinity.

 

[kbnh]

My alkalinity did increase from 8.1 to 8.9 because of the water change, calcium 435 to 490, magnesium from 1380 to 1490, however my nitrates were at 5 now at 3, phosphates we’re at .11 now at .8, would an alkalinity swing do this?

 

[AFHokie]

My alkalinity did increase from 8.1 to 8.9 because of the water change, calcium 435 to 490, magnesium from 1380 to 1490, however my nitrates were at 5 now at 3, phosphates we’re at .11 now at .8, would an alkalinity swing do this?

When I have a bump in alkalinity my cyphastrea loses tissue similar to that but can’t say for sure it’s the same.

All of your parameters jumped a lot which might be the reason. Do you always have that much of a jump when you change water?

 

[kbnh]

I usually do water changes much more frequently but I ran into low nutrients, cyano and diatoms which led me to not due water changes so I can build up nutrients, so I never had a swing this drastic before, my gorgonian is closed up a bit also and upon further review a new coral I put in looks to have similar degradation on it now