ROWAphos is slightly damp in the pot, this keeps the pores open inside the product to increase its efficiency. The tubs of come with an inner clear lid and the screw on cap, these should be enough to keep the moisture in. With the bulk 5kg bucket it is best to keep the internal bag tied up to retain the moisture content when storing. If the ROWAphos has become slightly dry you can spray a small ammount of RO water on to it to keep it hydrated.