how to find out if api test kit is expired

  1. redlessi Well Known Member Member

    help, just want to make sure my test kit is not expired. thanks much

    testing results in high nitrates 40, just did water change yesterday.
  2. Shawnie Fishlore Legend Member

    check the lot #s on each bottle..its suppose to have a shelf life of 3 years from those dates..the last 4 digits are the year and month they were made
  3. redlessi Well Known Member Member

    thanks much, now the question of why high nitrates the day after water change. its usually 20 and I do water changes every week.
  4. Shawnie Fishlore Legend Member

    could you have not shook the number 2 bottle hard enough? that is really weird...test your tap water ...maybe with the change of seasons, theres something in the water source\?