Coral Bleaching Out???

[sergiotami]

Does anyone know what could cause this??? Overnight, woke up and they'r really light in color.... My SG 1.024, temp 74 degrees F', checked ammonia, nitrates, nitrites, all read zero.... The only thing I did was the night before turned off the pumps for an hour and fed like I usually a mixture of Coral Frenzy, live DTs, Frozen Coral Mix..... All fish are doing fine....

[Big_Pun]

need to calcium, magnesium, alk levels. water changes, what water you use. so start

[justahobby]

When I read "overnight" my first thought was "temp swing". Then I saw 74 degrees. That's sounds very borderline and it sounds likely your tank dipped to 72 or so during the night which is certainly too cold.

Definitely need to look at the things Chris mentioned too

[sergiotami]

I have a 90 gallon RR Oceanic, I do weekly water changes using RO DI water. I just checked my calcium level and its one the high side, 480.... I night before the coral bleached, wife forgot to shut off cooling fan, got home to find temp around or just above the 73...Its been staying at 78 since then....