Some heads bleaching, some not on same colony

[Franken tank 2019]

So I have a large colony of Frogspawn in 2 seperate tanks and on both of them, there are a couple of heads bleaching randomly and the rest are completely happy. My nitrate are 25 and Phosphate is .12. I have a par meter and it's around 100 on one amd 200 on the other but the coral has been in this same spot for over 5 months and this only recently started. Curious what your thoughts are on what could be causing this. This picture was taken at night with filter so they were starting to close up

 

[fishguy242]

hi, shadowing ? tissue looks great, possibly consider fragging a few pieces off main.

 

[Franken tank 2019]

I don't think shadowing is the issue because the heads above it are good and there are ones lower and get less light than are still good. I was thinking about just cutting them out and putting them in a frag tank and see if I can nurse them back to health

 

[Franken tank 2019]

Here is what it looks like during the day

 

[fishguy242]

did they start out same as rest of colony ,and now changing ?
or did they start like this?

 

[Franken tank 2019]

The whole colony looked normal and good color. The bleaching is new.

 

[fishguy242]

I don't think shadowing is the issue because the heads above it are good and there are ones lower and get less light than are still good. I was thinking about just cutting them out and putting them in a frag tank and see if I can nurse them back to health

best plan...

 

[LuizW13]

My suspicion is a hot spot. Are you using LED's? On that first picture you added, you can clearly see a bleached head, along with unhappy heads in the middle of colony. Perhaps that is the concentration of light?

 

[noobreefer2]

My suspicion is a hot spot. Are you using LED's? On that first picture you added, you can clearly see a bleached head, along with unhappy heads in the middle of colony. Perhaps that is the concentration of light?

+1

 

[Franken tank 2019]

I am using radio g4pro with diffusers and T5 4 bulb supplement.