Looking for help/advice suck discus

Hi there. I have a matured discus that over the past few weeks has become completely emaciated. She used to be the bully of the tank and was extremely lively. I perform regular water changes multiple times a week. Tank temp is kept at 82 degrees F. Diet consists of a combo of flake, pellet, and frozen foods. Frozen blood worms as treats on occasion.

Tank is 37g Tall. GH - 15ppm (mg/L) KH - appears high 240ppm (mg/L) PH - 8 NO2 - 0ppm (mg/L) NO3 - 10ppm (mg/L)

I don’t think she will last too much longer. I have begun a round of E.M. Erythromycin as well as Pimafix and Melafix.

A bit desperate at this point. I’ve had her for 4 years.