Lobsters,shrimps,crabs,sand sifting sea stars, horseshoe crabs will all clean your "live sand" really well,of everything,except the bacteria. If that's what your calling"live sand"you have nothing to worry about.You can use any or all of them.If you have real live sand with worms and etc.you would be better off using cucs,some types of snails,serpent stars,mini stars,copods,amphipods.Do research so you will know how many of what to use.It's true that when something eats something in our aquariums it still will poop it out and nutrients will still be in the water,but each time something eats this poop(corals or whatever) a little less nutrient is pooped back into the water untill the bacteria take care of it or the algea in your refug. do.Research,research.