I have this black like hair algae on my substrate how can I het rid of it when o do a wayer change I vacum it up but still come back the only all tests came out good but the nitrate was a lil high
Thought Black Hair Algae only occured in FW tank.
You sure you don't have a new tank and have a Diatom Bloom starting? If this is the case, just leave it, they will go away by themselves in time.
One thing would be flow. Its a bacteria, you can blow it off with powerheads and stay on it. Check out your silicates, its feeding off something. New tank? Old lighting? If you have no coral you can throw Red Slime Remover.