Why are all my chalice dying off?

[notthatkindareefer]

Recently I have lost 3 nice chalice corals, one pink eye chalice, one large chalice that sort of looked like a raja, and a dragon scale. Now my cloudberry chalice is slowly receding. Any tips? It seems like all the chalice with raised “eyes” are doing fine but the more “flat” chalice aren’t making it.

Parameters-
Alk-11.2 which I know is high
Mag-1470
Ni-5
(all other parameters are within range/irrelevant)

 

[Cichlid Dad]

What are you using for substrate?

 

[notthatkindareefer]

What are you using for substrate?

Carib Sea Hawaiian black sand. Would not recommend, it is hard on my inverts and starfish trying to navigate across it, plus I have heard a guy mention it causing a spike in metallic content in his reef tank.