Algae Problems

This is a very close up photo of the algae in one of my aquarium tanks. I am treating it with JBL Algol. I want rid of it by the end of this year. It has been present in the tank for months now.

I have tested my tank and all the important levels are good (phosphates, nitrates, ph, hardness, ammonia, nitrites). The only thing that I do not measure is silicates.

The algae wipes off pretty easily from the plant leaves (but there are a lot of leaves in my tank). I am sending photos to JBL and the RHS to have it identified for sure. I'm not sure if it is blue/green algae or brown Brush algae (or something else). Any experts out there?

Just to stress .... the fish are all healthy and all tests are good.