Well my paramters otherwise seems to be ok.
pH 8,20
sg 1025
KH 9,5
Ca 400 (TM Ca/Mg)
Mg 1380 (TM Ca/Mg)
NO3 < 2,5ppm
PO4 0 ppm
I use Hanna Checkers for KH and PO4, Tropic Marin Ca/Mg test and Elos NO3 test. The lights are 5 months old and the Zoas were under it for 3 months already..
My open brain coral lost its red hue and became a pink one and now this is the second drastic color change. I dont know if they will ever recover. And i dont know what i should do , to give them a chance to recover...