I'd like to find out what is the cause of the high nitrAtes rather then band-aid it with treatment. Has anything changed? Gravel vac or something? Maybe you stirred up some debris causing a spike?
Water changes will be your best friend here. I battled high nitrAtes and did a bunch of water changes everyday until it went down and now I just stay on top of it. You shouldn't be getting high readings and putting chemicals and any other nitrAte removing products although will help it will only mask the bigger issue....
What is causing the problem.
This of course of JMO but adding things to remove isn't telling you what's causing it. Tap water, over feeding, bad test kit, etc...
I went through 3 nitrAtes test kits. I tested mine and it showed off the chart 160ppm+ went to the LFS and it was good. Brought my test to the LFS and it showed there water through the roof.
I called API 4x's on this eventually they sent me a new kit and I mailed them the one I was using.
Also you have to really really really shake bottle 2 very well. Bang it on the floor and shake, rattle and roll that bad boy.
Also it would be good like others have stated. Numbers would be helpful. Also size of tank, filtration, stock. Things like that will help others help you! And that's what were all here for.
So when you have time. Maybe answer some of not all o the questions and we can get this straightened out for ya.