On the big system like yours i would go with DeNitrator.
http://www.marinedepot.com/ps_search...~parsed~1.html
water changes are costly on that saize and would not bring No3 down anyway, because all that junk is stored in live rocks and sand bed.
http://www.jlaquatics.com/phpstore/s...uct_ID=cs-nno3
quote from J&L's site.
Nitrate troubles? Current research shows that sulfur based denitrators hold promise for significant nitrate reduction in heavily bio-loaded systems. These experimental biologically driven de-nitrator/reactors rely on a combination of pure sulfur, aragonite and sulfur reducing bacteria. NO-NO3® is that media.
i also like the sock and the hose water loop trick !