For a darker sand substrate, I know many people who use Tahitian Moon Sand (available at PetSmart and most LFS), which is a black sand. It looks great (especially in a planted tank) and no one I know has had any issues with it. The one drawback is you must make sure to clean it well before you put it in your tank, whereas with pool filter sand I believe it is already cleaned and ready to go.
Oh, and an ACF is an African Clawed Frog, but I don't know much of anything about them, except they grow larger and more aggressive than an ADF but are often mistakenly sold as ADFs.