So yes, chlorine tablets expire. If you can smell it, the chlorine is leaving your pills.Click to see full answer. Also question is, how long do chlorine pucks last? about one week One may also ask, how long do chlorine tablets last in storage? three to five years Furthermore, do pool chlorine tabs go bad? Tablet Chlorine At 36 months, InTheSwim tablets still have 98% of their original available chlorine, when stored in constant 50-70° F temps with a tightly closed bucket lid. In the right conditions, trichlor tablets can remain viable for over 5 years.Does chlorine bleach lose its potency over time?Bleach can expire. After a shelf life of six months, bleach starts to degrade. Even in its original bottle, bleach becomes 20 percent less effective as each year goes by. Bleach mixed with water at a 1:9 ratio (i.e. 10 percent bleach) is potent for about a day (it’s more unstable in its diluted form).