on/off bleaching paraancora

[kilnakorr]

Hi everyone and happy sunday.

I have tried finding the answer on why my paraancora is loosing color on and off / bleaching, but most info is the usual light, temp, alk issues which I haven't had any off.

It seems to lose color on some heads in the middle, then color comes back and another head is losing color. Been going on for a couple of months now.

Tank info:
350L DT+100L-ish sump
6-7 months old

Ph 8.0-8.2
Temp 25C
Alk 9 (have increased from 8 over the last 10 days beeing away.
Ca 450
Mg 1450
NO3 15-ish
PO4: 0.17

Nutrients a little high, as I recently removed my roller filter to get room for a bigger skimmer to get Ph up a bit.

I have around 80 PAR in that area, measured using a seneye.


It only hapoens to the heads in the center, like a horizontal band, so not those heads that gets the most or least light:

 

[Shirak]

Maybe it’s some sort of flow issue where the heads in the center are not getting as much. Or perhaps they are less likely to catch food. Do you feed them?

 

[kilnakorr]

Maybe it’s some sort of flow issue where the heads in the center are not getting as much. Or perhaps they are less likely to catch food. Do you feed them?

I don't think it's flow, as all heads move roughly the same.
I haven't done much direct feeding on this coral, so made sure to give it some a few minutes ago when feeding other corals.
Will try feeding it dircet for a while and see what happens.