What Is This Black Stuff On The Plant Leaf? Algae?

I am having a hard-time identifying the black thing on the leaf. It is also very hard to rub off. I do not see it looking hairy either.

Please help me identify it! Thank you!

 

Yep, algae. Can't actually see anything in the pic, but probably black hair algae or similar.

 

Yep, algae. Can't actually see anything in the pic, but probably black hair algae or similar.

Interesting, probably the beginning of BBA before it looks hairy.

 

Interesting, probably the beginning of BBA before it looks hairy.

Any pointers on how to get rid of it. I have it on my plants. I just ordered better lighting hoping that would help

 

Any pointers on how to get rid of it. I have it on my plants. I just ordered better lighting hoping that would help

I don't know about the black stuff on the leaves. I am double dosing Flourish Excel just to see if it will make any difference; otherwise, I will get a soft bristle tooth brush and try to scrub it off. We'll see.

 

At that stage fourish excel double dose or spot dosing might work setting up a co2 system would be better more long term solution as would more aggressive light control