euphyllia ancora did not survive

Hi, My saltwater aquarium (Red Sea Nano Max), with the following water parameters: Salinity: 1.023 Nitrate: 7.9 ppm Nitrite: 0.027 ppm Phosphate: 0.01 KH: 8.4 Calcium: 424 Magnesium: 1220 PH: 8.3 Ammonia: 0.0 Medium water flow Light setting with 75% blue and 15% white Position of the...