Campden tablets contain sodium metabisulphite and some binder.
Used to remove chlorine in water. 0,5g is suitable for treating about 20L of water.
Usage: add the right amount to your mashing and copping water. Mix well and leave for 5 minutes. Then you can start the treatment and your water will be chlorine-free.
Dosage: usually 0.5l / 20l water