Can raising magnesium bleach out coral?

[Animal-Chin]

I don't know what happened but my mag dropped to 1150 so I started dosing Mg Cl and have been raising it by about 100 ppm a day. Since I've started a big acro's bleached out, a little frag of monti digitata (but it fell off a shelf and landed in a LPS so that could have done it) and about a 1/4 of a favia brain. All within a week of each other.

I have 0 phosphates and 0 nitrates. Cal is 420 and Alk is 8.

Another thought is I've started fragging and I fragged a green slimer sps. Right after I fragged it it released a TON of slime, could that cause some coral to bleach?

Everything else in the tank is rockin. The only changes has been the fragging and the mag increase.

 

[Dav3]

Any changes to lighting or placement of the affected corals? What lights are you using? What is the temp currently? Is the temp in your tank constant or are there large swings? How old is the tank and how long have the affected corals been in the tank?

Are you running carbon?
When was your last water change?

 

[Dav3]

Also, what is your mag now? Overdosing can cause issues.

 

[Animal-Chin]

I'm running 2 120w LEDs on my 55. The coral haven't been moved and were added to the tank after I got the lights so there is no change for them. Temp could be an issue, the tank has been going from 80 to 82/83 during this hotspell but it's only done this maybe twice? Tank is 2 years old. Each coral has been in there I'd say at least 6 months. I am running carbon and change it monthly. I do 20% water changes every Wednesday using RODI water I make myself. Mag is now about 1300 raised from 1150 over about a 9 day dosing regiment.

 

[Daniel Fishy]

What's your lights on? I believe it's the lights I had to turn mine down never had them more than 60 blues and 40 whites now there 50-30 and that's we're they will stay.

 

[Animal-Chin]

50% Blue 50% white, do you think I should turn them even further down?

 

[Daniel Fishy]

I would and then see how everything responses. Tommy had the same problem I think he's running his at 30-30. I dont see how people can run them at 80 without having everything on the sand.