In my experience keep feeding the tank like it has livestock, dont do any water changes, and don't use any more additives. Nature will work it out. I have a feeling every time you intervene it slows things down. Usually the cycle takes 6 weeks. You may see a spike in ammonia and nitrite again but I swear... let it run its course.Its cycling for a long time and I cant get nitrite to 0. Water changes does not help. Do what to do
