Pureology hydrating shampoo is the one in the purple bottle.  It protects my color from the chlorine in the pool and from the head of the sun or blow-dryer.  My hair always feels healthy once I started using this shampoo and the matching conditioner.  When shampooing, it also leaves a tingling sensation on the scalp and a peppermint smell.  To me, this feels extra clean and invigorating.  I would recommend this shampoo brand to anyone with color treated hair.  This shampoo has proved to protect my color the longest and I now go 8 weeks between color instead of 6.  For those of you concerned...