Dude...there is no better clean up crew then themselves.Period.
You shouldn't be feeding them more than they can eat, or what you reasonably consider too much.
Look where in the water column crays live in nature.Things fall when missed, they live where it falls.And at the same time, you can feed less like that.As I like to do.Not only as a mini fast for them, but so they can get some cleaning done as well.
I've kept them in 2.5's with only airstones and they did the rest.Well I obviously changed the water.