When using one of the API 5 in 1 Test Strips, the results may appear to be inaccurate. To see what you can do in this situation, you can take a look at this article from Aquarium Blueprints.
1. For the first step, you should make sure that you are following the dipping instructions correctly. Basically, you should avoid exposing the testing pads to the air when swirling the strip in your aquarium.
When removing the strip out of the tank water, you should do so with the pads facing upwards. Furthermore, you should avoid shaking any water off of the strip.
2. You should also make sure that you are reading the test results correctly. When doing so, we recommend comparing the strip to the color chart in a well-lit environment.
3. If you dip the strip incorrectly, then you can try using a different strip to do the testing.
4. You should also use a different strip if one or all of the testing pads made contact with any other liquid aside from your tank water.
5. If the product has reached its expiration date, then it may not be as accurate as before. In this case, you may need to get new strips that are still fresh.
6. It is important to note that the testing pads are not as precise as liquid testing. So, if you want more accuracy, then we recommend that you get a liquid test kit.
If you are interested in one, then we suggest getting the API Freshwater Master Test Kit. You can check out our review for this product here.