I personally love the look of the black sand when I had it. It definitely made the corals pop more depending on colors. I didn't like how it faded somewhat over time and from what I've been told is it can be magnetic
Take a really strong magnet run over it
I wanted black sand as well but after doing some research i got that it wont reflect light so you wont have light in caves, back etc..
love the look though maybe next time
i personally dont like it i had it and when ever i would add rocks or corals or pieces of the rocks fell down it looked ugly after a while my sand looked like crushed oreo cookies. I think it looks amazing but i recommend rinsing of anything you put inside so no sand comes out of it