Algae in the aquarium floor?

Question

Hi, I've had this black algae on my gravel for a few weeks now. I don't know what to do about it or what it is. I've vacuumed it several times, but that only helped for a short time. thanks in advance

solomon22 · Answer

Hello. I think these are brush algae. Here's what you can do about it: https://www.drta-archiv.de/pinselalgen/

eieiei2 · Answer

These are brush algae. There is only more water change to reduce the phosphate value. In addition, it must always be close to the detection limit. After the measurement, adjust the fertilization if necessary and monitor the success by further measurements.