I'd be interested in any documentation showing that they eat each other.
I've been raising and selling them for almost two decades and have yet to find any such information.
The most complete information available for artemia is found on the United Nations article
Manual on the Production and Use of Live Food for Aquaculture, scroll down to section 4.0 Artemia.
My page, although not updated in a long time, shows how I've progressed over time.
Raising Brine Shrimp (Artemia)
Basically I use spirulina powder from Brine Shrimp Direct for making the greenwater to feed them with, but I also add a bit of Algamac 3050 to assimilate a better fatty acid profile in the flesh, and then I enrich before feeding using the Algamac 3050 alone.