Neutra Sul HP41N Professional Grade Oxidizer, Neutralize Rotten Egg Smells and Pollutants, 1 Gallon Eliminates Rotten Egg Smell Pro Neutra Sul is NSF Certified to meet NSF/ ANSI Standard 60 for drinking water additives For oxidation of impurities feed Neutra Sul until there are very few oxygen bubbles in treated water For oxidizing iron feed Neutra Sul at 2ppm per 1ppm iron Stabilized formula! Proven consistency over hydrogen peroxide 7%