Coralline algae bleaching

[Reeferdude56]

HI, my rocks have been slowly turning white, and my coralline algae has been bleaching. I read up on this problem and. I heard it has to do with light shock or calcium and alkalinity. Isn't light shock, I have had my LED lights for over a year now. I tested my calcium and alkalinity and my ALK seems a little low. My calcium is 480 and my alk is 7.3 what can I do to fix this problem. There are no noticeably effects on my fish and coral as of the moment. Any help is appreciated thanks!

 

[Reefing Madness]

Your ALK is a bit low but still in range, so is your CAL.
What is your Magnesium?

 

[Randy Holmes-Farley Verified Community Expert]

I agree that it isn't calcium or alkalinity.

Are other corals and such OK?

What does the bleaching look like? Spots? Whole sections?

 

[wangspeed]

Did you add something that eats coralline, like an urchin?