Tom,
What test kit are you using in getting such low results with nitrate testing? I see in your previous posts you are getting results in the tenths of a point range. Salifert . Viewed through the side and divided by 10; on a white backround it reads lighter than 2ppm ,once in a while somewhere between 2 and 5ppm. No discernable color at all from the top. Nitrate test are a pain but this has been very consistent on weekly tests.
What test kit are you using in getting such low results with nitrate testing? I see in your previous posts you are getting results in the tenths of a point range. Salifert . Viewed through the side and divided by 10; on a white backround it reads lighter than 2ppm ,once in a while somewhere between 2 and 5ppm. No discernable color at all from the top. Nitrate test are a pain but this has been very consistent on weekly tests.