be careful with the black sand, there are a couple of threads on here where people sent theirs out for testing when their coral failed to thrive ror even survive and it had elevated rates of some kind of element that was killing their coral. I think the info was in "turtle's deep blue" thread.
I've been using black sand for almost 15 years. And know many who have used it long term as well with zero problems. To be blunt my opinion on black sand being a big problem is about the same as blaming the ceramic media blocks for coral issues