It is generally advised to avoid sulphates on your strands as much as you avoid them on your scalp. If you feel that you have build up from your pre-shampoo, we'd first advise you to revise which pre-poo you chose and the quantity you are using. The point of pre-poo is to protect your hair but not to make it so 'dirty' that you need a sulfate shampoo to clean it afterwards. That would be counter productive :) If you're utilizing Shampoo A, Shampoo B or any other shampoo from our Luxury Haircare Formulation Guide, you can always add more gentle surfactants (like coco-glucoside or soap nuts) to boost the cleansing power of your shampoo. You can also get cleansing benefits from your conditioner, which contains emulsifiers that break down the oils in your hair without stripping the strands.