We have noticed the scum in our SBR tank has a green tint to it. We have two SBR tanks, and this is only happening in one of the tanks. The sludge is healthy, settles good, no strange odors, and decant looks great. We have not made any air or mixing adjustments. We have researched and researched, still can’t come up with any answers. Is there anyone out there that has experienced this or knows someone I can contact?