dont even know what detritivores are lol, subtrate is about 1 and half inches deap and its just marble chip aragonite stuff i get from LFS here in Aus. about 2 - 2.5mm grade the tank has 2 big turbo snails, a occelaris clown and a dusk blennie in it, it has been setup for about 2 and a half to 3 months now and has been fine so far.