Unique Marine Digest-It is a green cleaning product that packs a powerful cleaning punch. Use this inexpensive and effective natural cleaning product to completely eliminate odors and clogs in your boats water systems. Use it in your gray or black holding tanks and you'll never have problems dumping. We guarantee it! Using billions of healthy bacteria, Unique Marine Digest-It will turn everything in your holding tanks into liquid and it works in salt water! It is also a great solution to ridding your bilge area of odors.