Montipora bleaching?

[Specialk1012]

Hi all,

I came downstairs this morning and part of my montipora had turned completely white. Any ideas as to what this is?

ca 430 ppm
Alk 10.6 dkh
Mg 1340
No3 0.62
Po4 .02
Temp 79.7
Sg 1.025

I did have a small alk issue over the last week (dosing pump got stuck on) and alk ended up at 11.8 and I have been slowly bringing back down to my 8.3-8.5 target.

 

[Mrtakeoff53]

PO4 looks a touch low IMO. I Always had the best color and growth with montis when my PO4 was 0.06-0.12. However, that small spot looks like it got stung. Any corals colors to it? If it keeps growing RTNing, just cut it out about 3/8-1/2” into the good flesh. They grow quickly. You won’t even notice it in 6-9 months.