I like the black sand. Still have no background yet, but what we want to do is get some butcher paper and have my ten year old paint it. He did a van gogh style painting last year in art class that was very, very nice...u know the one with the castle silohuetted in the foreground and the moon and sky swirls of color? We want to give him some dark blues, greens and browns with a bit of white to play with. think that would look great against the black sand we already have.
The sand we got was from the LFS, and it took alot to get the residues off. I rinsed it prior to putting into the tank, but was still nasty. Ended up emptying the tank and washing the glass twice before it was actually clean enough to fill. Lesson learned.