We're sorry to hear that you are finding the chlorine colours difficult to distinguish on these test strips. We do supply alternative test strips and digital test strip readers which might be worth investigating if this becomes an issue for you - or please feel free to discuss with one of our water care experts. The following video may also be useful in ensuring your testing procedure is getting the best results from the test strips: https://youtu.be/YhAcS6DhBew
