Birds nest random bleaching small part of colony

[Bitcoin Reefer]

My birds nest has small section that randomly bleached quickly. Just noticed another part next to that part bleached also almost a week later. Parameters pretty stable, but we’re moving about 3-6 weeks ago. Stable for last few weeks. 8.5 alk, 480 calcium, 6.1 nitrate, .14 phosphate.

I have a coral crab that lives in this colony, so I’d hope he’s cleaning it of potential pests. I do have some clear flatworms in the aquarium.

 

[Lavey29]

I'm not really seeing it. Corals look healthy.

 

[Bitcoin Reefer]

In back/top of the 1st picture it’s clear. In real life it’s paper white, harder to see in photo. It’s completely and fully bleached/dead. It’s white on very top, then below that it’s brown because algae grew on part of it.

 

[Lavey29]

In back/top of the 1st picture it’s clear. In real life it’s paper white, harder to see in photo. It’s completely and fully bleached/dead. It’s white on very top, then below that it’s brown because algae grew on part of it.

Ok, I see it now. Frag it off if you can in case a bacteria infection so it doesn't spread.