Filter that removes nitrates from water

[Hawaiianfishkee]

Two notes on that:

1) If you are growing plants hydroponically (only roots in water) then they are releasing O2 into the air, not the water, so you will still need mechanical oxygenation.

2) Most plants prefer ammonia to nitrites or nitrates, so you may as well skip the bacterial filter and use plants for the whole process.

Plant filters are very effective, the only real drawbacks are the space they take up and the lighting requirements.

I was planning this, be easy on me. I am going to have a syphon(maybe separate overflow) from tank to a mid level hydroponic setup maybe a shallow rubbermaid with greens floating on styrofoam or something that allows water to run under the greens, and have a drainage go directly to sump(mechanical and bio) then pump back up to tank. So the whole process would be by gravity. I just don't know wether I should divert main overflow or a seperate overflow to divert to green setup. Any thoughts? what would would u do?