First off, good you don't drink that toxic sluge - do send a sample to a company (google it) and they will confirm or prove it is false.

Until then, an algae scrubber is 100% the absoult best way to go - utterly cheap, easy to maintain and so simple it is a crime. Unlike R/O which requires constatnt replacement of expensive 'filters' the algae grows and consumes the nitrates (and other organics.) You clean out once a week and that is it.

There are special biological filters that consume nitrates but these are not cheap and can have issues. I have one and it killed all my discus - enough said.

The algae filter I have has done wonders and works; I bought mine fully ready/assembled for $60 and it handles my 75 gal tank and (at the time) my tap had 10 ppm nitrates (low compared to you but did make me very ill.) Kits are lower in cost and you can build one even cheaper.

I simply do not believe you'll ever have enough plants to consume even close to that much nitrate; however, plants and an algae filter might be the best way to go. But no plants will ever consume that much nitrate unless you add high lighting, CO2 and any missing trace nutrients ... so, moderate plants and an algae filter is your best solution.