Yarr!! Looks like ye ole Black Beard!
Do you have shrimp in this tank?
Caleb
Since you don't have shrimp you can harm i would suggest a low dosing of H2O2 spot treatment. I do this for my discus tank, burns the algae right off!
You can get calculators on google on the safe amount to use for your tank size.
Caleb
And just to be clear, once I have shrimp that kind of treatment would be a bad idea?
Shrimp can be sensitive to it. Once you get the shrimp you can switch to Excel.
Just take a syringe and squirt it right on algae. You will see it bubble up and start fizzing.
Some people turn off filters though I've tried it both ways and seen it work both ways.
Caleb
It will keep coming back till you fix the issue. Look at co2, flow, light, and nutrients. Try and get things in balance.
Best thing you can do is plant easy growing fast plants. Get some floaters too to help reduce light intensity. I generally see bba in newer setups before things get into balance and plants are still in transition or just not thriving.
My number one way to help.slow down algae is to cover 50-75% of my water surface with duckweed or frogbit. Algae stops.