hard corals turned white!!!

i have 4 hard corals that were red and i went on vacation for a week and had my friend feed my fish and when i came home all of my hard corals that were pink turned white. water params are good but the alk was low so i did a 25% water change and added some alk buffer any ideas please. thanks

 

They Bleached or RTN'ed ? if it was RTN then they are toast toss them.

 

Do you have a picture? Bleached corals still have flesh on them They will smell like coral. RTNed coral have no flesh and are dead with no smell and algae will begin to grow on them

J

 

yikes.... usually i thought bleached corals = dead?

 

i dont know why they turned white all of a sudden. im pretty sure there dead because they dont produce any mucus when i touch them. any ideas why?

 

Here is an article on RTN... ReefHQ Aquarium :: Coral Disease.

 

Nope a coral can recover from bleaching.

That does not necessarily mean there are dead low ALK can also cause a loss of the slime coat but it too is recoverable.

ALK, PH, Temp, SG can all cause both Bleaching and RTN could something have happened while you where away?

J

 

no i dont think anything happend, my alk and mag were low so i put in my norm chemicals and there still white hopefully they will come back.

 

Hope it works out I had a couple corals bleach in my tank. (Thank god the were the cheaper ones) But sometimes they will come back. One of mine did and is doing pritty good now.

 

what causes bleaching in the corals