i dont no if you have tried this but try doing several water changes. like one or 2 everyday one morning one nite. or if you dont want to stress the life in the tank then just do one a day for a week straight then check your nitrates. also how much live rock do you have in your tank. Do you have a skimmer and what kind do you have. lets have the details of the tank
size of tank
live sand, reg. sand, BB
filtration (live rock, cannister filter, HOB filter, Skimmer)
Water movement (powerheads)
water quality (ph, salinity, ammonia, nitrites, we already no nitrates).
# of occupants in the tank & wat are they.
let us no what you have from the up above criteria so we can help you better. you might not even need that device you listed.
and deepwater is dead on the money the bioballs will cause more nitrates so u dont want that.