I don't know if my eyes are ready for the red type. I had no desire to sleep last night and an overwhelming desire to sleep now that I have eight hours of work ahead of me. Ugh...
OK since you are still sleepy I will type in a more soothing color
After reading your answers I'll elaborate on my questions from last night:
Since the grown discus are such gentle giants do they even need to be a mated pair to occupy the same tank? Would a third discus throw off the peaceful nature of the tank?
I'll research the Geophagus compatibility. I've read of a few people keeping them together. My Geophagus are really well behaved unless they are cramped for space and even then the aggression is only between themselves. My German Ram routinely thumps and chases the Geophagus even though the Geophagus is about three times the size of the ram.
When I had rams they thumped my disus taking the poor discus by surprise regularly when they were guarding their spawning site. Rams fear nothing! LOL!
I doubt the Geophagus will out compete the discus for food. Mine are primarily bottom feeders unless the flake food won't sink.
Discus will grab food from the water column and also the surface, but then they will spend a long time after feeding grazing the bottom of the tank for the food that drops.
Tell me if I have this correct- Discus are schooling fish and aggressive amongst themselves when being raised but their temperament calms down and they are OK with being in small groups as adults. Right?
Yes. Every now and again you will run across an adult who is a life-long bully, no matter what. I had one. Key word HAD. She was so disruptive at feeding time especially that she stressed me and the rest of the discus out all the time. I rehomed her. Peace and tranquility set in immediately upon her departure. Adult discus aren't nearly as worried about being first to the food to grab the most nor to keep part of the tank to themselves as young growing discus are. Even when I have 2 adults spawning in their tank, there's only minor pushing away from the intended spawning object (filter intake).
What is the lowest temperature that I can keep my discus at and still have them happy and healthy? I currently keep the Geophagus at about 81-82F and they seem to be thriving. I know I'll have to go up from 82F but how much? 84F, 86F? Adult discus can be kept at a temperature a bit lower than young discus. 82-84 is ideal.
I think that my smaller Geophagus is convinced he is a clown loach. He spends all day swimming with them. It's pretty funny actually.