When kept in temperate, dry storage without exposure to UV light or strong oxidizing chemicals, the shelf life of Sponge Media is "nearly" indefinite.
We are often asked about the shelf life and warranty on Sponge Media. While the warranty is limited to 1 year from the date sold by way of our authorized distributors; the shelf life is nearly indefinite. We have tested our media after 25 years (a quarter of a century) of storage and confirmed little to no degradation in performance which leads to our determination of "nearly indefinite" from a practical view point of how old materials may be in circulation.
Storage of Sponge Media in moist environments for long periods of time may lead to mold, while exposure to UV light or strong oxidizers (like ozone) may lead to a weakening of the sponge matrix. These conditions should be avoided through the storage life of the media. Clients reasonably ask why we limit the warranty to 1 year if the shelf life is so long. The reason is that we can not reasonably track storage conditions of media once it is out of our control and out of our managed distribution chain. Therefore, after a year out of our known storage conditions, we do not feel we can guarantee full product performance.