Finalized Aquascape - Opinions Needed!

[I3raven]

So this is my aquascape after about 5 days. My tank is 20 gallon long that is dirted with organic soil. My lighting is a F15T8 15 Watt Fluorescent light. Unfortunately, after planting the dank, most of my plants have melted or in the process. I am interested in buying a liquidized CO2 supplement such as Excel or API CO2 booster. But, some people do mention that liquid co2 supplement can cause plants to melt. Are my plants compatible?

Plants
-Marsilea Hirsuta
-Cryptocoryne Wendtii Green
-Flame Moss
-Rotala Indica
-Dwarf Sagittaria

The first image is my Marsilea Hirsuta and is the plant's leaves are turning brown..is this suppose to happen? Anyways be completely honest about my aquascape and list some recommendations. Thanks!

[Hawkian]

I've had plants melt on me after using excel so I have vowed never again. If you are worried about co2, why not use a DIY reactor? It's cheap and easy.

I do believe that your plants are merely going through an adaptation period though... They will eventually come back with new growth.