4 inch sugar fine DSB, cheato to help take up excess nutrients, some nessarius snails to mix up some of the sand, tons and tons of little creatures for feading the tank above and to break down detritus, extra rock and some extra rubble I use for frags and finally some softy frags I am letting heal and attach to rubble rock.
Live rock rubble (less needed in display), macro, xenia (removes nitrates), hitch hiker snails, & shrooms,
and at times- anything that doesn't want to play nice!
I have a rubber ducky floating in mine. I was told it helps reduce stress while doing maintenance.
I just run 3+ inches of sand with some rock rubble and a small clean up crew (nass snails and 2 turbo's). Also any hitchickers i find that are not supposed to be in the main tank.
Hopefully I can culture all kinds of crittery goodness in mine. This is where patience & me have to make a truce, I like things to happen now, but know it takes time.