I even have Scuds in my aquariums and they are very industrious little creatures. Almost like tiny Elves running around with a broom and dust pan cleaning up after every thing. Dead and rotting plant matter, left over food and anything else laying around not being used for anything.

I have them in the tanks with my Electric Blue Crayfish. The Scuds, who in addition to keeping the tanks clean, are also fed upon by the crayfish.

I don't suspect they create much in the way of nitrates but every tiny bit counts