Is putting weights on my ludwigia what’s killing it?

Hi all!

I use fluval stratum in my fishtank and as a result, the plants don’t stay in it too well unless rooted very well.

I got these bendable metal weights for my ludwigia and wrapped a small piece around the bottom and stuck it into my soil.

However, they won’t grow. I’m not sure if maybe this is killing them? They seem to be dying/melting from top to bottom!

I dose easy green and I’m going to start dosing flourish potassium.

Thank you!