You are probably right. I do not know how to breed them, so don't believe me 
Some hobbiest told me that difference is it, that discus in natur get all they nutrient and minerals what they need from water and food, but in aquarium water is quite poor and that's why it's important to give enough nutrients, vitamins for young discus. So conduction of electric should be over 150-170 ms too, when raising them.
dGH 12 sounds guite high still...
Anyway...
Edit. I found this article when searching information using his name.
Some hobbiest told me that difference is it, that discus in natur get all they nutrient and minerals what they need from water and food, but in aquarium water is quite poor and that's why it's important to give enough nutrients, vitamins for young discus. So conduction of electric should be over 150-170 ms too, when raising them.
dGH 12 sounds guite high still...
Anyway...
Edit. I found this article when searching information using his name.
