It was a nice read, but there are a few things I disagree with. I think its a bad idea to lower the temp to 76 F/24 celcius. Its simply too cold. And as you said yourself, many of the rivers where you find rays are small tributes. The water runs slower and the temp will stay around 79 F+.
Also, I dont see why you think batman rays are a result of high temperatures. Batman rays are also find in the wild.
I am farly sure it is a genetic defect. Again, they are found in the wild too.
Also, I dont understand why you are telling people to turn down their heat in combination with a salt sure. Its true that the bacteria will have an easier time, but so will the rays immunsystem. That goes for all tropical fish.