Discus With Various Illnesses [ Velvet (Oodinium pillularis) & Hexamita ]

Hello, days ago my fish tank temperature dropped abruptly and my Discus got ill. They appear to show symptoms from Velvet and Hexamita. My tank temperature at this moment is 84 degrees Fahrenheit, I've been treating the community tank with ParaGuard since two days ago. In two fishes I've noticed some recovery, however, other Discus still remain not eating and with symptoms of Velvet. This morning I saw signs of Hexamita in the tank. I measured the water parameters and they are good. The capacity of my tank is 120 gallons, with a total of 8 3 inch Discus. If anyone could help me I would be very grateful. Thank You.