By 2 tank for breeding, at least you have to prepare 4 tank to raise the fry.
By 20 gallon tank, you plan to do to raise them up to size
? and how many?
In our farm, we always prepare at least 3 tank 30 gallon to every pair of our discus for the fry when they big enough to eat arthemy shrimp, because the pair of discus will laid eggs again at least one week after
and 5 tank 60 gallon for the raise from 1 inch till size measure 3 inch to every batch (100-250juve).afterwards we split them by 3 division: candidate for mains and contest,export quality and ordinary ones.
And for illumination at breeding tank, discus prefer smooth light, because they are romantic fish
. If for grow tank, its okay
Hopefully this small information can assist you to realizing Discus Breeding Center which you wish
What kind of discus you wish to breed?
Dont forget water treatment and correct drugs for your discus.....
Good luck