I'm very particular about having bright white sand too. I have 1 sand sifter starfish in my 90 gallon, and a really really fat mandarin. My only complaint about my sand sifter though (and I'm sure its just mine) is that he doesn't like to go to the back half of my tank. There's plenty of space for him to get to it, he just likes to go back and forth along the front glass. Which I guess is fine because the sand is as white as the day I bought it. But the backs hard for me to get myself and unfortunately doesn't look as nice as I'd like it too.
Anyway, I'd get a starfish and about 20 nassarius snails.
Anyway, I'd get a starfish and about 20 nassarius snails.