I decided to remove the discus fish, and now all the plants seems to grow.
keeping discus in a non mature aquarium is very difficult, the amount of food requires raise the nitrate level to above 50ppm.
unless you have an over planted tank, that level of nitrate is just algae inviting.
in this tank, i have to keep nitrate 5ppm at most, other wise algae takes over rapidly.
i trying to create a flat carpet aquarium for discus display, in this layout over planting just won't work design wise.
i thought about planting lots of stem plants in the beginning, then remove it later once mature, yes, but the stem plant will block the light, hence my glosso won't grow well.
for this tank, what works is keep the nitrate very low.
EI doesn't work either.
i only dosing KCl and sometimes iron.
with this setup, sometimes the new glosso show pale color, but I'm just gonna have to live it that. keeping nitrate low is the only way to keep algae at bay.