Solves holding tank odors by eliminating them at their source. K. O. works when nothing else will. - A safe, non-chemical and non-polluting product. A small amount of K. O. can easily keep a boat odor-free between pumpouts. Does not require adding tissue-digesters or other boosters to be effective. Once it is open, it has a one year shelf life. Can't be stored below 40 degrees.