Could an unopened bottle of CDS from 2018 still be good? I just found 6 bottles.

Thank you for your response. I would hate to waste them if they still had potency. I opened one and it smells potent!

Hi TQ. They are quite old and probably have lost some CLO2 during that time period. If they have been in a dark place and cool or cold, they are still useful.

CLO2 gas tends to stay in a water solution (CDS) if kept below 50 degrees F (10C) and not exposed to light, especially sunlight. So, don't open them unless they are cold and be sure to recap the bottles as soon as you finish taking out a dose. If you have CLO2 test strips, you can test for CLO2 concentration, ppm.