Thanks for the answer, my corals (leather umbrella and kenya tree) are more or less 3 to 2 years old, the anemone is more recent and has 3 months in the aquarium. I use Luminaire A052 Gako 52w
Could very easily be the leathers releasing toxins and the nem not liking it. carbon can help. Any other issues with snails/hermits? Want to rule out copper. It isn't abnormal for magnet enclosures to bust and the magnets slowly leach heavy metals into the water.
Idk anything about that light so can't really make suggestions there beyond asking if the light is new to the tank and the inverts started looking after installation.