API tests are inaccurate as far as liquid test list go. It is a color match, which means it’s very hard to distinguish exact readings.Funny thing is the strips don't have anything like silca gel to help keep moisture out of the test strip containers. Plus they don't test for ammonia. I prefer the liquid API test kit, and also haven't has any issues with one reagent/solution running out before another for those kits with a two part test.