How to clean this mold?

So we’ve had this in our basement ever since we bought the house about 5 years ago. We did have poor grading outside the foundation and that has since been taken care of, although I don’t know that to be the ultimate cause of this mold.

Anyway, can I just scrub this stuff off the wall with a utility brush and then spray this mold treatment on it? I apologize if I sound dumb, or if that’s an awful idea, of which, I’m lucky I checked here first. It’s just that I know how the internet has a way of over-amplifying dangers and “diy” things like this. I don’t want to call in a pro who will do the same thing I’m asking about.

See attached pictures.

By the way, can this stuff cause coughing/allergies? The furnace is about 4 feet to the left of it. I’m just thinking that folks have mold in their walls, and air ducts for decades and never know it… right?

Imgur: The most awesome images on the Internet