I like your discus Cichlid-man and pure,
I used to have a pair discus, cardinal tetras, and a pair GBR in 29 gallon high, when my GBR was spawning, the male get really aggresive/protective even towards the discus! Lol.
but I moved, so I sold my discus and my tank and move on with much smaller tank with only tetras which is easier for me to move around.