No, stagius, it's all in how that's worded. Purigen adsorbs nitrogenous waste, that if otherwise allowed to remain circulating would break down to form nastiness. It doesn't take the actual nitrate and other ferts dosed out of the water column. Seachem has lot of information on the website about it, but basically it's a macroporous polymer resin that adsorbs very small particles. Though, I think even Seachem says they don't know exactly how it works.