Sodium Metabisulphite (SMBS) Pickling Solution Mix
With proper care, your reverse osmosis membranes will last for years. Due to the nature of reverse osmosis, the membranes self-clean while the system is in use. However, when the system goes unused for an extended period of time, the membranes need to be “pickled” to ensure rotting microorganisms aren’t in your system and damaging the membranes.
The powder itself is food grade sodium metbisulphite and dissolves easily in cold water. It is safe and widely used in the food and beverage industry.
This chemical is widely used and available easily from home brew and wine making retailers, among others.
A material safety data sheet can be found here.