To give you some background. Set system up ~3 years ago with Marco dry rock. System has never completely settled down.
started bare bottom but about a year ago added sand ( bagged live sand). Over the past 3 years I have treated Cyano, hair algae, and Dino’s. The brown rock covering appears like a mulmy covering.
I have tried and tested many things, have taken ICP tests thru Triton and ATI. Both tests show ro/di di water very clean and system water to be in good ranges. Nothing on either test shows anything outside of range. You would think something out of range but doesn’t.
I have tried low nutrients including running gfo and refugium as well as running higher nutrients. Neither seems to have any impact.
curious if anyone has info or identification on perhaps something I haven’t tried.