Sodium carbonate, also called washing soda, has a strong degreasing power and is a great water softener. Its used throughout the house for laundry, dish-washing, house-cleaning and DIY projects. Its most common use is as a laundry detergent optimizer for hard water. Osmose Sodium carbonate if very useful for the maintenance of washable diapers and heavily stained laundry. Softens hard water. Non-toxic Vegan, cruelty free Septic system safe