Clownfish adopted Rhodactis Mushroom

A few days ago, one of my Clown fish adopted the Rhodactis Mushroom. The second Clown joined in today. The coral doesn't seem to be stressed.

Tests; NO3=5 ppm, PO4=0.03 ppm, Calcium at 460, KH 7, SG 1.022, Temp 24'C.
Calcium is a bit over the line. Will stop dosing it for a week and see what happens.
SG is a bit too low, will do next water change with higher salinity.