There is only 1 way to get nitrates to 0. And it's not by doing pwc
. That will only lower it by a small percentage. You need something to consume nitrates. Anaerobic bacteria in a reactor will do it well and so does plants and algae Preferably cheato in a sump. A skimmer of course helps PREVENT nitrates by removing the stuff before it converts. But it will never be 100% effective either, otherwise our live rock bacteria would not be required.
So if yours are building up, pwc
will help slow it, and eventually what you remove will be what builds up since the last pwc
but your remaining will be higher.