So Ive been going through a dinos outbreak the past few weeks. My tank did fine at 0 nitrates for most of its life, until I unplugged the protein skimmer and plugged it back in a few weeks later. Nitrates went up a few ppm and then when I plugged it in, nitrates went to 0 and dino outbreak. Last week, I decided not to change my mechanical filtration (poly-fil) and so it has been sitting in there for 2 weeks instead of the normal 1 week. Nitrates are now detectable. Does mechanical filtration remove nitrates? I have always read that it does not.