I think most unopened/unused water conditioners have a shelf life of about 16-24 months. Once its' opened/used its' effectiveness decreases to a few months. So I guess it depends on if your bottle is brand new or if you've already used some of it, (plus the amount of times it's been used & exposed to air and other outside influences.)
...Treat it like you would eye drops or juice in the fridge.
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