nassarius snails work great at sifting the sand without the ill effects of eating the infauna, cerith however have to be my champs as they reproduce extremely rapidly, which provides a constant source of zooplankton in your tank...sand sifting stars work well, but i fear that they prey on the sand life as well....same with the cukes...the cukes work by taking sand in one end and pooping it out in pellets from the other...
p.s..be very wary of sea cukes offered for sale in the trade....there are many in the family Holothuriidae that get extremely large and can possibly eject their cuviverian vesicles...the tiger tail cuke, Holothuria impatiens, or the Impatiens Cuke, is a great detritus feeder, but like all cukes can possibly expell its cuviverian tubules (intestines that are extremely sticky and can trap and kill fish)which can lead to the cuke dying and releasing the chemical Holothurin which binds to fish gills making the uptake of oxygen impossible and virtually choking them to death.....we recently received one of these guys in on a shipment that had its tubules ejected in the bag....it was recorded as DOA!
again do your research before placng these animals in your tank
and hair im pretty sure it was Donkey Dung, not Dong....hehehehehe freudian slip perhaps??????
hehehehhehe
good luck
jon