Bare patch on bottom of acro

[JoshLTX]

It came to me like this, has been in the tank for a month. What should I do? I’m seeing new growth and coloration on the top but not sure what the cause of this was.

Params are staying pretty close to this range, testing 1-2 times per week:

 

[shakacuz]

seems like old damage/die off that is being grown over by new growth. likely from being shaded.