I understand. But, that API test kit just takes too much time to use. If you have several tanks like I have, taking several minutes to test the nitrogen and other levels is too time consuming. I've found over several years, if I simply remove and replace most of the tank water every week, I can skip the testing. If I faithfully change most of the water every few days, I know the water chemistry is always steady. Besides, if I need a nitrogen reading or need to check the pH, alkalinity or hardness of my tank water, I can use a testing strip and get a fairly accurate reading in 60 seconds.
"Fear not, my young apprentice. Just change the tank water."