The "beta" fish, that is the one that tested the external system while the others tubbed around the aquarium, died. My assumption is that the pH swings from the algae plus the increasing ammonia levels plus the temperature swings from our nicer than usual weather plus the stress of adding two new fish to "his" tanks was more than he could take. I will run the tests tonight and I filled the vertical 55 gallon barrel for a water change tomorrow.
I performed a basic necropsy of the carcass and did not note brown blood disease. Sad.
Following the adage, I only have kill 9,999,999 more fish until I'm an expert.