Arum Lily Root rot keeps coming back

[happyc4t]

My wife and I started some basic hydro setups a month ago. we got Monstera, Coleus, and Poinsettia, they're all thriving in water, but her Arum Lily is a nightmare!
We cleaned it up once after the roots went brown and mushy (we suspect it was totally submerged at first). We trimmed the rot and set it up with way less water (like my other plants), but now the roots are rotting again!

It's in a simple pebble pot with drainage, sitting in a container of water. just like everything else that's doing great.
I'm 90% sure it's a persistent bacterial or fungal infection in the roots now. Before I try treating it, what do you guys think? Why is this one plant so miserable?

 

[camel0pardalis]

Arum lilies can be picky about water. Try raising the pot so just the very bottom of the roots touch the water but not the whole thing. If you can, add an air stone to keep things moving. Also, is the container sitting in direct sun? Warm water can speed up root rot.

 

[frothic|approach]

Recurring rot in an arum lily often tracks to warm, low-oxygen water. Keeping the solution in the 65–72°F range and boosting aeration are key. For the persistent infection, consider a flush using 3% hydrogen peroxide at 2–3 ml per liter, followed by reintroducing beneficial microbes after 24 hrs to prevent it from coming back.