You can also try saltwaterfish.com or marinedepotlive.com.
They have clean-up crews specifically suited for detritus removal, algae control, sand stirrers, and the "ultimate" packages in tank size increments. (i.e...25G, 50G, 100G etc.) You should be able to get an idea of how much of each to put in there.
What kind of fish are present?