Uh oh, the voice of logic, watch out. You are right, chloroquine phosphate is chloroquine phosphate, whether in a jar for the aquarium or a pill that people take. Now, that's assuming that the aquarium stuff is legit and doesn't contain other ingredients. Medicine that people take has to meet percentage values and is tested to make sure as part of the manufacturing process. Lots of pills that people take have a lot of filler to create the tablet, I'm guessing they didn't realize that. Apparently in an interview the lady said they each took a teaspoon of the stuff, which I'm guessing would be like 10x the normal dose. So yeah in the end they were still dumb for doing it, a case of a little knowledge being more harmful. The other thing is that drugs tend to cause worse side effects in elderly people with health conditions or just being old, not to mention the high likelihood of drug interactions since they are probably on 1/2 dozen other things.