hhhmmmm.....so as of late there has been alot of PPL (atleast 2-3 others) I know of that have been having the same problem. I dont believe its the white ring diesease. If it were me i would cut the coral just above the white ringd area and reglue it, the cure for white ring so happens to be to put superglue around the area above the ring to seal the coral off. So by cutting the coral and reglueing it this is what u are doing. Dont wait to take action, the other ppl did wait trying to do WCs, Carbon, GFO etc..CUT and RE-GLUE make sure to cover the whole end of the fresh cut area with superglue. This is just my observation, If the coral isnt being stung then its something wrong with the coral. Matt use ur best judgement, do what u feel is the correct thing to do.