I am also replacing the white river-sand in my tanks with black sand from Garnelen Guemmer and it looks really good! Below is a couple of quick phone-pictures.
My TangTaiTibee-tank is giving me some nice surprices in the form of small blue and red steels. My red steels resided there for a few days before being moved to their permanent tank so they might have something to do with it.
Red steel in the middle.
Blue steel in the middle.
A few new additions is coming the next couple of weeks. Nanashi, PRL and so on. It will be exciting!