Some advice on hatching brine shimp just from personal experience:
At room temperature you may get some start to hatch after 24 hours. Most will be hatched after a total of 48 hours. Put a light behind them and move the light around. If your eyes are as bad as mind you will need glasses to...
I have had discus turn dark after a heater malfunctioned and they developed Hexamita or spironucleus. Their feces turned white and I had to treat with Metronidazol and 95 degree water. They got better after a couple of weeks. I think all discus are susceptible to this if they get stressed...