What would you do if you get a nitrite test result showing your nitrite levels are at 0.8-1.0 ppm? At least I would panic at first. Just take a look at the picture below and you see what I mean.

The result to the left is the one I got from my first sample and it got me panicking for a brief moment. It shows a nitrite test result as high as 1.0 ppm which basically means that my fish are about to die. At this point I was still wondering how this could have happened since only a while ago the results were fine. What could have happened?

Then I thought I better take another test just to verify the reading. That result is in the middle in the picture above. As you can see it looks normal. I confirmed this by measuring the nitrit level a third time and you can see the result of that one on the right. This also showed normal. What had happened? All of the tests above were taken withing 5 minutes of each other.

Well, when I took the first test for nitrite I also took a test for nitrate. I had the both test bottles in the same hand shaking them violently to have them mixed well. This is what the instructions for the JBL nitrate test says I should do – but the nitrite test does not say I should do this. Apparently if you shake the test bottle of JBL nitrite test too much, you will get a false positive reading as a result. I never thought that shaking the test bottle would cause any harm – I mean it was not explicitly forbidden or anything. But apparently you shouldn’t do that. Only gently see that the two different liquids you dropped into the water are mixed and leave it alone for three minutes.