Thanks for the thought, I think I'm gonna give it a bit of time and then maybe try something else back there.Have you checked your phosphates? Club soda contains potassium phosphate. Perhaps 5ml weekly of club soda would help.
If it's DIY in low concentrations CO2, Java Fern will do great.Hair grass at least needs Co2 additive. Java fern are sensitive Co2 additive.
Lilaeopsis chinensis, which you have been talking about, looks like it will grow similar to Dwarf hair grass and doesn't need a lot of Co2.