Hard Coral and Rock look grey.

[newbeemike]

My tank has been up and running for about 3 years. Have not had much problems. Grew a lot of purple and green coraline algea. Rocks were looking great. Lately my rock seems to be lookig grey. and some of my hard coral also look grey, like they are stained the same as the rock. Not sure if anyone else has seen this before. I am very confused. . I changed my lighting about 3 months ago. Went from power compact to 2x250 watt sunpod metal hallides. Please help.

 

[yote]

The change in light has changed the PAR and lumens your coral was getting.
So basically,its browned them out.
Quick changes in lighting can cause things like that to happen.

 

[newbeemike]

what about the rock looking grey. is this the same reason.

 

[dustin_P74]

the light difference probably bleached the coraline

 

[reeffreak]

You went from low-moderate lighting to intense lighting.The type of coralline that grew well under PC will bleach/die except maybe in shaded areas.Some coralline adapt to the intense lighting but most likely it will be replaced by coralline that can handle the intense lighting.I've always found slower growth in coralline when under intense lighting than moderate lighting.

If your corals are looking pale(whitish).Now is a good time to place them near the bottom,shade them or use some kind of screen to shield them from the light.

 

[Bifferwine]

You will need to gradually adapt your corals to the new lights. You can do this using the methods Freak described. It will take a few weeks for the corals to get used to stronger lights.