Was just looking at the Kelpak website and came across this:
'After opening, we recommend that Kelpak be stored in a cool, dry area and be used within 3 weeks. Since Kelpak is made from a natural source, it is susceptible to microorganisms in the environment. Although these microorganisms may grow on/in Kelpak after opening, the beneficial activity of the product remains intact for long periods of time, however, clogging of irrigation or spray equipment may occur if fungal growth does occur.'
After opening, we recommend that Kelpak be stored in a cool, dry area and be used within 3 weeks. ??
