Yes I just now noticed a best by date: 09 19. Feeling silly lol .....l remain committed to get better at this. Must say that my pool is now somewhat clear. l removed so much leafs and pine needle like 20 lbs. I am going to keep filtering and need to slam again this weekend. I could not completely follow through and maintain slam level this week that I did start last Sunday. Just concerned about my test kit being good to go before I go back at it tomorrow.