My orange diamond goby(Valencienna puellaris) does a kick butt job of keeping the top inch of sand sparkling white. I have nassarius, conches and cerith, but none of them kept it near as clean before I got the goby. And I've been lucky I guess, because he loves any food I put in the tank.
I've had 2 in my 180 for awhile now. They process a ton of sand every day... I don't think they're hard to keep. I do nothing special for them to keep them thriving.
-Yes, he does this because he is hunting and then eating all the living organisms in your sand. The secret to a healthy sand bed is to have a wide diversity of these organisms, your goby will not allow this to take place.
Steve
I have an olive snail ( he is BIG) but i seldom see him, about 12 nass, i mexican turbo, 2 bumble bee (always in the rock), 6 turbo and 1 margarita snail ( she really works, need to get more of them), but what really sifts my sand is my Tomato clown LOL...