Light is very deceptive without a PAR meter.
My 100PAR @ the substrate doesn't appear all that bright to me.
I cannot distinguish the 75PAR side from the 100PAR side without the meter.
Did some searching tonight and found this thread, from those values I should be just under 90par at substrate level on max setting: https://barrreport.com/threads/chihiros-led-lights.13977/#post-138447
Macrandra japan for me looks like pig vomit until the tops reach 8" tall.
Then they are in a much higher PAR range, they begin branching and showing bright red tops.
When trimmed the tops look like hell again until that right height is reached.
Three years of growing this and I've only offered for sale once due to poor appearance.
I noticed it is looking a little better as it gets taller, seen that with several other plants. Wasn’t sure if that was the higher light or just recovering .
I would rule out CO2 @ this time.
My fert schedule is so different using capped soil, can't chime in on that one.
Dropping KH down should help improve as you have done.
S. repens for me is growing 5" tall and branching even in semi-shaded areas of the tank.
PAR meter, anyone you could borrow from ????
Im using Brightwell, very similar to controsoil. Like Ada but much leaner on nutrients. Not sure I should be dumping so much ferts into the water column or not. I figured it would cover most deficiencies, but reading some of the other threads I’m not so sure I don’t have too much of something. I did see improvement going from about half current levels to what I’m dosing now, but none going higher than that. I guess I’m stuck not knowing what to adjust, just raise/lower one thing at a time and see what happens.