In the newest version of the official Sands of the Desert instructions, there is a step-by-step method for making your own Black Water Pouches.
These pouches use a special pigment to turn the water a dark black very quickly, with little stirring (Black Water Clear Water is required to turn the water clear again). Instead of gathering the necessary supplies yourself, here is everything you need ready for assembly.
Turn clear water an eerie black—easily—with the Black Water Pouch Kit!