It seems strange that AFA carries a variety of other brands though as well. I believe Archaea is AFA's own brand as well. I don't want to speculate on ADG, I just wonder if they moved on to NA for other reasons.
Yes, but Archaea is a line that offers products that aren't really meant to compete with ADA, but give an alternative. If they started making glass pipes/diffusers/tanks and substrate, I don't think ADA would be happy with that. This new company, however, is in direct competition. They offer pretty much the same line of products with similar designs and concepts. And according to ADA:
Thank you for your support for Nature Aquarium Goods, and Do!Aqua goods. In the U.S.,we have been so far marketing our products through, Aquarium Design Group, but as of July 25 2013, we terminated our distributorship agreement with them over the disagreement on marketing approach of our products in the U.S. market. We apologize for this sudden termination decision, and inconvenience it may cause to the end users and retailers in the U.S.
I haven't heard much from ADG on their side, but they haven't been great at communication/PR as of late.
My Golden Rule of planted tanks: WWTAD-
"What would Takashi Amano do?"