RV Holding tank cleaner. Certified-green and environmentally friendly.To meet stringent EcoLogo criteria, a holding tank additive must:control odors and help decrease waste materials. Be biologically-based and non-toxic. Not harm humans or riparian and aquatic species. Not accumulate in the environment and have limited surfactants that biodegrade. The Formaldehyde-Free Formula: quickly breaks down and liquefies waste and tissue to prevent messy clogs, has superior odor control, contains a detergent additive to keep tanks clean and the non-staining green dye washes clean with soap and water. Available as a liquid or Toss-Ins for the ultimate in convenience.