Tell us the dimensions of the tank, the light fixture manufacturer, a link to that light fixture, what fertilizing you do, if you use CO2 and how. That will help us find clues about what that is and why it is there.
Hi VaughnH, thanks I’m using an ADA 60p tank, so it should be 60x30x36. The light fixture is a local brand called Nana Uno, its rated at 30W. It supposed to be 60W, but I only on one strip of LED. I’m using ADA Brightly K, only dose 2 times a week.
My LED and co2 is on a timer, which I’m normally turning it on only 6 hours. The tank currently was set up around 3 weeks plus.
How do you adjust your CO2 bubble rate, to be sure you are using an optimum amount? That light looks like it produces high light, primarily because that is a fairly low tank - the closer the light is to the substrate the higher the light intensity. With that much light you need to experiment with the CO2 to be sure you are supplying enough.
I think I would remove the hardscape and scrub the existing algae off of it, to get a new start.