The shampoo you learn to make on the challenge counts as your 'sulphate free shampoo'. Therefore you don't need to find another one to add to your routine in addition to this. Having said this, it can help to have a 'back up' sulphate free shampoo if you know you are going to struggle to make your DIY shampoo regularly. So, having a second option in this case can be helpful for those days that you are unprepared but need to wash your hair. You will need to add a sulphate shampoo to your routine as this is what you will use to reset your hair 1-2 times a month. You will also use the sulphate shampoo to remove any resilient silicones if you use these in your routine!