Acro bleaching question

[Kiiyo]

I'm still new to acros and what causes them distress so I'm looking for advice on how to deal with what looks like bleaching to me.

Parameters:
Alk ~8
Calc ~ 490
Mag ~ 1300
NO3 ~ 0
Po4 ~ .1
Temp ~ 78F
Salinity ~ 34-35ppt/1.025sg
Par for this particular coral is around 175 and it does get adequate flow that causes the polpys to visibly shift continually throughout the day.

I noticed these white areas developing in the middle/lower half of 2 frags of the same coral that are in 2 different locations in my tank. This led me to believe it's a parameter issue, and just from looking at my parameters, I'm thinking it's a nitrate issue.

I noticed a white spot like the one in the photos maybe a month ago on one of the frags. While it did heal completely, it's appeared again recently.

All other acros look normal, so I'm thinking this may be my canary in the coal mine coral.

I'm also feeding heavily twice a day with pellets and frozen food to my 7 fish and I spot feed the acros twice a week at night.

Now I'm considering dosing sodium nitrate or potassium nitrate to try and bump up my nitrate, but wanted to see if there might be something I'm missing and this isn't a nutrient related issue. I've also decided to cut down on filter sock replacement and lowered my refugium photoperiod significantly from 12 to 3 hours.

Any advice is greatly appreciated.

This is the other frags of the same coral located under higher light. On the right frag's base, there is also a similar white area showing that you can faintly see in the picture. Same deal, single whiteish area, doesn't look like bleaching I've seen the past.

 

[tbrown]

Is it possible it's growth? Sometimes growth tips And growth ridges can look almost like bleaching. Zooming in on the pictures almost looks like new growth to me but I can't really tell for certain. One thing I do notice - your nitrates are 0. That can be a concern. Just a quick question: phosphates and nitrates, what are you using to test? API? Salifert?

@Fish Styx

 

[Kiiyo]

Is it possible it's growth? Sometimes growth tips And growth ridges can look almost like bleaching. Zooming in on the pictures almost looks like new growth to me but I can't really tell for certain. One thing I do notice - your nitrates are 0. That can be a concern. Just a quick question: phosphates and nitrates, what are you using to test? API? Salifert?

@Fish Styx

For phosphates and nitrates I'm using Hanna checkers. I don't think they're new growth based on how quickly they've formed and the location on the coral, but that would be a welcome surprise.

 

[Mr. Mojo Rising]

I would not use the word bleaching in this case.
How long have you had these acros? I don't see any basing on any of them, thats what I look for first with acros. Acros can take months to acclimate to a new tank.

 

[Kiiyo]

I would not use the word bleaching in this case.
How long have you had these acros? I don't see any basing on any of them, thats what I look for first with acros. Acros can take months to acclimate to a new tank.

Interesting, do you have a better word to describe what this is? It doesn't look like bites to me because it's 1-2 larger spots rather than many small ones.

Maybe 6-7 weeks in the system, and aside from the frag on the rack, they were glued down maybe 4 weeks ago. They have started to base and show new growth from where they were fragged.

 

[Mr. Mojo Rising]

Maybe 6-7 weeks in the system, and aside from the frag on the rack, they were glued down maybe 4 weeks ago. They have started to base and show new growth from where they were fragged.

To me this sounds normal, sounds like its still acclimating IMO.

I really can't answer about the white part, I've never experienced what you described, happening twice is definitely weird. Personally I would observe and see what happens next, the coral looks very healthy to me otherwise. I know Its not a good answer I'm sorry, but its what I would do unless someone gives a good explanation. Good luck