Take a look at this large tank from a article on reefbuilders.com ( near the end of the first youtube video) that uses miracle mud.:
http://reefbuilders.com/2012/12/06/e...d-mixed-reefs/
Quite impressive results from just using mud in the sump especially with the amount of fish and so little fancy equipment.
From what I read, the mud provides minerals as well as the bacteria that should be replenished even couple of years.
regs
msjboy