Okay, just curious, you did check that the test kit wasn't expired right and that you did follow the instructions correctly? the only reason i ask is because ignoring either of those two points could lead to false results...
Also, how often do you clean your filters in the tank? coz if you clean too often or not enough that could possibly also be the problem?
Also, how often do you clean your filters in the tank? coz if you clean too often or not enough that could possibly also be the problem?