FWIW, I've used Tahitian black moon sand before and hated it. It is very fine and easily sucked up by a gravel vac or filter. It also shows waste very bad.
"What, exactly, is the internet? Basically it is a global network exchanging digitized data in such a way that any computer, anywhere, that is equipped with a device called a 'modem', can make a noise like a duck choking on a kazoo." - Dave Barry