euphyllia glabrescens - polyps spin

[Sin3d]

Hello, please help me.
Did someone have such a problem that the polyps of euphylli glabrescens were starting to curl?
Initially, it pumped normally and it was ok, and over time the polyps began to screw in.
What is caused by this behavior?
Parameters:
Kh 8.3
pH 8.6
Mg 1230
Ca 430
Salinity 1.023
Po4 0.1
No3 0.2
NO2 0

 

[A Young Reefer]

not sure if it has a direct effect on the polyp shape. but salinity of 1.023 is somewhat low don't you think?

 

[Sin3d]

I know it's low but it doesn't seem to have any effect. Other ideas?