FAQ: Does Seachem Purigen® exhaust, expire, or need to be replaced?

Sealed and unopened Purigen® does not expire over time, but an exceptionally old bottle of Purigen® may have become contaminated, or the seal may have broken.  If Purigen® has an unusual or rancid smell (it is normal for Purigen® to have a "fishy" smell), has completely dried our, or has turned an abnormal color (i.e. grey, blue, etc.), it is recommended to get a new packet or tub. Note that variation in color from white to cream to yellowish is normal.

Once Purigen® has been added to the aquarium, it will start to absorb organic waste from the water.  Purigen® typically turns deep brown as it exhausts (although other colors are possible if unusual waste is present in the water).  Once Purigen® has completely turned to dark brown, it can be regenerated using the posted regeneration instructions.