It should remove a lot of dissolved organics before they can break down into nitrates.
Could you point out where you read that (not brow beating, just curious )? I would strongly disagree with that statement though. Some levels of nitrate are not harmful for many coral types but we are talking <10 ppm. 40 ppm for most coral types could easily lead to bacterial infections, including many soft corals.Electrobes said:they actually suggest having a ppm of 40 of nitrites for soft corals.