Help!!! Corals Bleaching

[gamma]

I have a few acroporas bleaching. *I have one completely white, and 2 more that are getting there. *I have a few other acroporas that still have their color, but I'm worried that they might also get bleached. *My water params are as follows:

alkalinity - 7 dKh
ammonia - 0
ca - 435
nitrite - 0
nitrate - 0
pH - 8.0
phosphate - 0
sg - 1.024
temp - 77.0

Not exactly sure what needs to be done at this point. *I've reduced my lighting to the following schedule:

4:00 actinics on
5:00 mh's on
11:00 mh's off
12:00 actinics off

I know my pH & alkalinity are on the low end of the spectrum. *I'm working on it. *Any ideas? :'( :'( :huh:

[gamma]

did i stump everyone?

[amcarrig]

What do the corals share a tank with? When did they start bleaching?

All you can do at this point is try to save a few frags by snapping them off above the point that they're bleaching

[Jason McKenzie]

Are they just turning white or is the flesh flaking off? What are your Day night temp swing? are they Frags from another colony or are they wild caught?

[gamma]

they're turning white and the flesh is flaking off. i believe most of them are not frags and are wild caught.

What do the corals share a tank with?

i have several inverts sharing the tank:
nassarius snails
red legged hermits
blue legged hermits
yellow sea cucumber
blue linkia star
fire shrimp
cleaner shrimp
purple lobster
bubble tip anemone

only 1 fish:
domino (killed my pair of clarkii clowns, a few days ago - he's going to a new home - the fuge!!!)

the corals started bleaching about 10 days ago. one thing I didn't do was acclimate them (i know bad). is it too late to acclimate them to the lighting using screens?

i'm currently using oceanic sea salt and have been advised to switch to natural ocean water, which i'm considering.

any thoughts, opinions?

[amcarrig]

Well, not acclimating probably played a big part in their bleaching but I too am wondering if you've had any temperature fluctuations?

I wouldn't switch from sea salt to sea water at this point as I don't believe that it will stop your corals from bleaching.

The only thing I can advise you to do at this point is to start fragging and hope for the best.

[Jason McKenzie]

Most bleaching is not because of lights. It's not a fadeing of colour do to too strong of light.
How long have they been in the Tank. Wild caugh SPS are a lot more sensitive to change than frags. I just lost a wild tricolour do to temp swings. Or at least that is what I think.

J

[JohnO]

Gamma,

I'm no expert, but from what I have read the coral is not bleaching. What you have is RTN

Refer here

http://www.netpets.com/fish/referenc.../schiemer.html

Quote

" There is a big difference between bleaching and rapid tissue necrosis. The latter is loss of tissue whereas in bleaching no tissue is lost.
In RTN the polyp tissue starts to disintegrate, often at the base of the coral, and sloughs off. If water it directed at it, the tissue detaches from the coral and floats around, the tissue is dead. "


John