What does the lot code and date label on One & Only mean?

The lot code is just a way for us to track the manufacturing and bottling process of One & Only. The lot number does not have a special code; it is just the lot assigned to the batch of One & Only bottled at that time. The “best used by” date is the date we recommend one uses One & Only by. It does not mean that One & Only will be totally ineffective after that date, only that the efficacy of One & Only will have decayed, but using One & Only will still establish a biofilter faster than doing nothing at all.