Why did the BART Test for Nitrifying Bacteria turn yellow instead of pink?
Yellow color formation of Nitrifying Bacteria BART tester
The BART Test for Nitrifying Bacteria (Product # 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.