Hey guys newb here, It’s only at the base of my Duncan and nowhere else and where it’s missing tissue. More visible under all blues, doesn’t blow off but scrapes off easily. Wanted an expert/pro opinion maybe @vetteguy53081 could offer some insight before I proceed with the h202 dip/ toothbrush. I did just rid my tank of Dinos(nutrients bottomed out due to media I was chasing numbers lesson learned)

