Treat your tanks with Odorlos for absolutely no holding tank odors! Odorlos eliminates all holding tank odors without masking perfumes or staining dyes or using formaldehyde. Formula speeds up the natural composting process, breaking up waste and tissue and lubricating valves. One Odorlos packet treats a 40-gallon holding tank. 10 per pack. Speeds up the natural composting process Breaks up waste and lubricates valves | ODORLOS EZ Pack Drop-ins, 10 Pack