Yes all kits eventualy contact manufactur for exsact experation limmits. Of you want a good way to test it take atleast a shot glass of water to a ***** or any other store and have them test your water with their kits. (*****'s do this free) then test with your kit and se how off you kit truely is some reading my be slightly diffrent with diffrent kits but should still be in the ball park. I hope this helps you.