When using the Organic Dread Shampoo do I HAVE to also use the regular dread shampoo? - Dreadlocks FAQ's
No, of course you don't HAVE to =]...It's only a recommendation but if you are planning on keeping your dreads for many years and you want to be certain that there are no residues being left behind, it's a really good idea to give them a deep clean, once a month, with the original Dread Soap. People have started and maintained dreadlocks using shampoos that leave MUCH more residue than our Organic Dread Shampoo - Are their disadvantages? Sure, sometimes they end up cutting their locks due to dread rot...but if you're planning on only keeping them for a year that may not be a concern. The bottom line is that 99.1% residue free is really close to residue free so it's unlikely that you'll ever experience any downside due to residues, but why not be SURE? A deep clean once a month is cheap insurance.
It's also worth noting that since drying time is effected by dread size - the thicker your dreads are the more important it is to keep them clean on the inside so they dry as fast as possible.