Dwarf Water Lettuce Advice

I settled for Dwarf water lettuce because it's the only floating plant my LFS had in stock, but I've never kept it before.

I know it doesn't like turbulent water and I did change the flow around a couple times before I got it where I want it. Could have done long term damage? It's been calm smooth surface for 4 days now. My kid stomping around the house disturbs the water surface more than anything, and I can't really stop that realistically.

Last 2 days I've been finding whole roots caught in the filter and hung up on my moss and monte Carlo. The couple leaves that got waterlogged I expected the melt on, but others are spontaneously getting darker/translucent spots and the healthy leaves are going yellow around the edges.

My lights are not exactly standard for tanks, I know, it was a cheap solution using this grow light and I'm not totally sure how far from the water surface I need to keep them, so I wonder if it's too much light? Nutrient situation should be pretty solid based on the hard water and rotting shrimp I'm using to feed the cycle but I don't actually have any live animals in yet so would this be a deficiency of something? It's been less than 2 weeks of them in this tank, so I didn't expect to have nutrient issues at this point, and did expect to be past the initial shock of transfer.