Pest ID affecting birdsnest and stylos

[Yanir34]

This is STN (soft tissue nicrosis) and can be caused my many factors such as:
Often its as simple as flow or light and things overlooked. Often siphoning dead tissue and brown gel will reverse the process.
Some possible triggers of infection are:
- Alkalinity spike
- Temperature spike
- Salinity spike
- Low dissolved oxygen
- Poor water quality related with phosphate levels up to 5 ppm
- Change in water flow
- Additions of sand
- Changes in brand of salt
- Bad test kits giving faulty results
- Levels of minor elements such as Iodine, Potassium, Strontium
- Light intensity
- - Changes in water flow
- Addition of new corals
- - Pesticides
- Airborne Contaminants or sprays

Check for PO4 swings.

it's definitely can be the cause for this RTN.

 

[Om84]

How did it end up going?

After treating my tank with interceptor I have had no problems growing stylos and birds nests. I’m still not 100% sure of the cause but I believe interceptor helped.