Wet dry filter\ refugium

O.K. I need a little help here, I have a 65 Gal tank, a wet dry filter, and a canister filter, still having some elevated nitrogen problems, do I need a reefigum? What is a sump. do i need one of those? I am a little lost here.

 

Every tank could use a refugium. Try filling it with mangrove shoots, they're really good for nitrate export. As to your other question a sump is normally used in place of a wet/dry. It is basically a tank that holds the protein skimmer, the return pump, and your biological filtration (LR is the best for this. If your given a choice, choose that over bioballs, less work in the long run). Some people incorporate their refugium into a chamber in their sump. Some people also run both a sump and a wet/dry, sometimes turning the wet/dry into a refugium.