thank you for the advice I've just ordered the api kit so I will keep in mind a separate test for nitrates if I have any problems reading the resultsOnce my tank is stable, I only occasionally test for nitrates. For nitrate test, I use seachem nitrate test...it's a lot easier to use and to read the results than the API nitrate test. API is good for PH, Ammonia, and nitrite tests but their nitrate test is a pain to use and hard to read.