colaline turning white

[Parnold]

what does this mean? Its turning white around the top of the tank.

[Keri]

If it dies it turns white, it may have died if your water level was low for a while.

[Boomboy]

yeah if its exposed to air usually it turns white, like say when the tank level goes down for water changes.

[chevyjaxon]

my guess is dead, no worries though in time it will regenerate!

[Tom R]

My guess is it is dead. If you let your water height fall or during a water change the coral line algae is out of the water too long, it will dry out and die. This happens very quickly if you have your MH lights on at the same time.
It will grow back over a period of time.

Tom R