corraline turning white

[zlwags85]

A lot of the coralline in the tank is turning white. All the levels are stable and calcium is above 400 still. Was just wondering what could be causing this. thanks

[Benny Z]

have you changed lighting recently?

[brad23]

My MH killed most of mine

[zlwags85]

Yea, i changed lighting in january, but most of the corraline that is turning white is new since the lights

[David MC Lee]

check your S.G.

[zlwags85]

Would a high salinity kill it? The salinity was at about 1.026-1.027 which i lowered over the coarse of a couple hours to 1.025, which is where it is normally at.

[Sk8r]

Temperature. Doublecheck your thermometer, both in the sump and in the display. Get a second one to be sure. If the water blows down overheated, that's not good, and it takes the rock longer to cool down; bleaching will start in 85 degree water.

[zlwags85]

The temp has remained between 80-82, I have a digital thermoter, float thermoter, and the thermoter that sticks to the glass. I dont have a sump or refugium and the heater is in a high flow area, so I dont think that is the problem.

[rick rottet]

is it only up high??? if the water level drops down during a water change, sometimes the corraline gets exposed and bleaches beacause it either dries out, or gets exposed to much brighter light

[zlwags85]

surprisingly, all the coralline that is higher in the tank is still alive and fine, all the coraline in the bottom 1/3 of the tank is bleached and dying.