I need advice

Hi im not new to fishkeeping but I am a novice at planted tanks.I've
got a co2 reactor I built myself which runs into my powerhead for
distribution.
My plants are:
1)Wysteria 4)Amazon Swords 7)Ammania A easy to grow red plant
2)Java moss 5)Bacopa mint 8)Baby tears
3Dwarf hair grass 6)Lud Repens

My plants arent lively, probably due to the substrate which is sand.
I plan to place my plants in clay pots with aquatic soil rather than
tear the whole tank down. That and the fact that I'm not sure what
direction to go with a substrate suitable for plants.
Have you got any advice for me on whic direction to go? I really want
the plants to flourish, but they aren't.Any and all advice you have
would be quite welcome.

Thank you very much, Jay