Bullet gobies. Diamond gobies. All do a great job of sifting sand, but be careful what you ask for. They can make mounds of sand on top of corals or other places you don't want sand to pile up. Two spot gobies aren't that way as they sift only smaller amounts, but they die quick. Yellow headed sleeper gobies are similar to the diamond and bullet gobies, but they often perish as most don't eat prepared food and rely on the sand to nourish them. It won't sustain them for long.
Nothing can keep sand clean like a decent vaccum of its surface (not too deep) at water changes IMO
Also, your nitrates all WELL within an acceptable limit. 10 or zero is better, but lots of folks would kill for 20.