man, i changed my substrate from crushed coral into sand. what a mess! ask that guy how often they change the sand in the ocean lol.
if you have any problems just suck the top layer and funnel in some new to put on top. i assume i may do this just for looks from time to time.
protein skimmer, and clean up crew should get plenty of nutrients out of that stuff. maybe even some burrowing creatures? like a sea star?