Nitrate test kit issue

[GJW]

For a while now I have been happy with the Nyos nitrate test kit. I decided to give Salifert a try today and noticed it was showing 0 nitrates while the Nyos is reading 20-30. I want to believe the Salifert result as my Hanna phosphate checker has been trending down lately and it is also at 0. Has anyone experienced anything similar or have recommendations for me? I am aware that bottoming out nitrate and phosphate is not ideal I’m just not sure if I should increase my feeding overall or dose phosphate.

 

[GJW]

I found an old API test kit laying around. This also shows 0 nitrates. Looks like my Nyos test kit is very off.