Why did the BART Test for Nitrifying Bacteria turn yellow instead of pink?

Document ID

Document ID TE3924

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
Why did the BART Test for Nitrifying Bacteria turn yellow instead of pink?
Summary
Yellow color formation of Nitrifying Bacteria BART tester
Answer
The BART Test for Nitrifying Bacteria (Catalog Number/Order Code 2619407) will typically turn pink, pink-red to show a positive reaction. If a yellow solution is formed, this would indicate high levels of Nitrite in the sample. It has been found that levels greater than 3 mg/L of Nitrite can start to cause problems with the N-BART tester. For the solution to turn yellow, this would indicate Nitrite levels above 20 mg/L. This yellow color can be interpreted as a positive for high levels of nitrifying bacterial activity, but a control should be done using sterilized (autoclaving or membrane filtration, 0.22 micron filter) sample. If the sterilized control does not exhibit a yellow color, but the regular N-BART does, then this would indicate a very high level of nitrification occurring.