To answer your questions:
The pH is 7.2 and our water is very soft. The water temp is the same all over the tank and is now at 80F. Ethel has stopped scratching, but she's hanging around the top of the tank, fins still clenched. She has very dark coloration and won't eat.
I do water changes AT LEAST weekly (more often than not, 2 x weekly) I have never had a problem with brown algae, but it'a all of a sudden "bloomed" in the tank. I believe this could be due to our tap water having too many nutrients for it to feed off (as we have well-water).
I'm very concerned, because I've had this tank for 8 years, with no problems. Upon doing further research, I believe Ethel may have velvet fungus, but I'm still unsure about this.
I don't like treating with chemicals and antibiotics unless absolutely necessary. It's about 2:00pm here now, so I have about 5 hours before the lfs closes, in case I should have to get them. I will hang around to see if there are any more suggestions on this topic, but will definitely have to start the guessing and dosing game soon. Thanks for the help.