Acropora bleaching causes

Samandar · Nov 16, 2018

Hi, help please. As you can see in the Pic. my acro has been bleached in the root, where it sits on the base.
No3 _ 5
Phosphate _ not detectable
Cal_455
Kh _9
Mg _1410
Potassium _ 260
What could be the cause or causes of this matter?

Jonreefer · Nov 16, 2018

shaded, so tissue basically died off.

declanisadog · Nov 16, 2018

It looks like it's getting shaded from the growth above.

declanisadog · Nov 16, 2018

Jonreefer said:
shaded, so tissue basically died off.

beat me to the punch

Crabs McJones · Nov 16, 2018

I don't know that I agree with the shading answer. I have several acros that have grown into colonies and have shaded parts that are colored up and looking great. I'm more inclined to think that its STN from alkalinity swings or a nutrient being off.

afartindolphin · Nov 16, 2018

Over what time frame did this occur and is it still progressing?

declanisadog · Nov 16, 2018

What sort of lighting do you have? if it's tissue necrosis, it doesn't matter, but LED only tanks are notorious for having shaded spots that look just like that. the acro below has look like that for a long while, and is obviously otherwise healthy.

Samandar · Nov 16, 2018

afartindolphin said:
Over what time frame did this occur and is it still progressing?

From two weeks ago it began. Yes it is going forth, unfortunately.

Samandar · Nov 16, 2018

declanisadog said:
What sort of lighting do you have? if it's tissue necrosis, it doesn't matter, but LED only tanks are notorious for having shaded spots that look just like that. the acro below has look like that for a long while, and is obviously otherwise healthy.

The lighting panel is a diy.

afartindolphin · Nov 16, 2018

Samandar said:
From two weeks ago it began. Yes it is going forth, unfortunately.

You said your phosphates were undetectable, what test and do you use gfo? Might consider reducing the amount if so, zeroing phosphate can be a trigger for tissue necrosis. Sometimes it will stop on its own and the coral is fine, others it may continue until the whole coral is dead. Keep an eye on it and if it starts traveling up the smaller branches fragging above the dead tissue is always an option.

declanisadog · Nov 16, 2018

I also notice there isn't really any PE going on. Is that how it has always been, or did the polyps go away when the tissue started receding?

Samandar · Nov 16, 2018

afartindolphin said:
You said your phosphates were undetectable, what test and do you use gfo? Might consider reducing the amount if so, zeroing phosphate can be a trigger for tissue necrosis. Sometimes it will stop on its own and the coral is fine, others it may continue until the whole coral is dead. Keep an eye on it and if it starts traveling up the smaller branches fragging above the dead tissue is always an option.

I have refugium and ats. The test kit is salifert.

Samandar · Nov 16, 2018

declanisadog said:
I also notice there isn't really any PE going on. Is that how it has always been, or did the polyps go away when the tissue started receding?

Before it began to bleaching it was OK.

Samandar · Nov 16, 2018

So, what do you think about potassium? Could it be the cause?

afartindolphin · Nov 16, 2018

Samandar said:
So, what do you think about potassium? Could it be the cause?

260 seems low but could be testing inaccuracy, not sure how it would get that low unless your salt mix started out low or if you hadn't done water change in a very long time. Water changes or potassium chloride to get back to 400ish might help but a fast change back up might also be bad.