Question: what is the difference between soda crystals and caustic soda?
Answer: Caustic soda is sodium hydroxide and is a more 'aggressive' product than Soda Crystals (Sodium Carbonate Decahydrate). The confusion may occur because Caustic Soda is commonly used to clear blocked drains; our advice is that it's best to keep drains clear in the first place, before they become blocked.