Denitrator.

[cabezon]

you might put the intake into a HOB, or in front of a canister outlet. it really needs low flow. too fast and it wont work.

 

[VonUberReefer]

get seachem matrix for the media in it, that's independant of water flow.

just as a side note, for the discussion of water changes.
i know a guy, who had 400 some gallons in his system, between a 125 tank, a refuge, a sump, and a frag tank.
he's got the best coral tank i've ever seen, there's probably more coral than water in the main tank. seriously i have yet to see any better on the net or wherever.

he only does 10% wc's once ever 4 months.

just something to think about.
i think it's the refuge/sump combo more than anything else but /shrug

 

[handb94]

cabezon that is a good idea. I am using a shut off valve to meter the flow. I read that the outlet has to be a fast drip.

Uber Thanks for the media suggestion. That is some crazy filtration to do changes that far apart.