Oh what a difference the substrate can make!
In my previous tank, I was using soil capped with eco-complete as the substrate. Which I figured would be a great substrate for a low tech crypt tank... It seems it all depends on the soil. My fancy soil from the bag actually contained mostly peat moss, though I was too inexperienced to understand the difference at the time. For two years my plants sat in that stuff and struggled, and I could never get the tank to look healthy.
This time around, I'm using mineralized top soil, made with good old Portland dirt, dug directly from my back yard.
The difference has been immediately apparent...
Compare the old leaves to the new: