SIMPLE INGREDIENT - Environmentally safe phosphate designed to soften water and leave no hard water scale RINSES CLEAN - Rinses completely from fabric, leaving behind no residue on your clothes that can irritate sensitive skin HARD WATER TREATMENT - Removes problem minerals from your water such as calcium that keep detergents from working NON-TOXIC - Water softener for hard water and well water that aids in natural biodegradation in the environment SEPTIC SAFE - When used in moderation, formula is safe in septic and municipal water systems. Non-precipitating and will not form scale Some wander this Earth seeking wisdom. A lot of folks Charlie talks with are looking to beat hard water. Our Booster is a hard-water treatment made from a non-toxic biodegradable phosphate that brings out the best of Charlie’s Soap without leaving any residues on your clothes. It controls minerals in your wash water with just 1/2 tablespoon per load. Your septic system and washing machine will be safe, too, because Booster is completely soluble.