Planted Tank Guru
Join Date: Nov 2009
Location: Missouri united states
I onced asked the same question regarding foreground plant and it was suggested that the foreground plant's,or carpet type plant's aren't so much needing higher light, but rather they are more in need of Good CO2.
CO2 being a gas, that is trying to escape,,the lower carpet area's don't receive the CO2 without increased delivery of same,and good flow to try and keep CO2 mixed throughout the water column at steady rate's .
For your application,, I might try something like Marsilea,Ecinodorus tenellus,Pigmey chain sword,or dwarf Sagittaria.
My two cent's.