Peace lilies as nitrate remover but...

Duckweed would be eaten, pothos may get the roots nibbled. Better to keep it in a filter or sump, or at least somewhere in the tank they can't get at it too easily. Water lettuce does require good lighting and air circulation.
 
Yes. I'd say pothos would be even better because producing all those vines is much more aggressive growth than with peace lilies.. thus, using up even more nitrogen.
 
Either one will be more beneficial to the plant than the water quality, but it helps. You need a large amount of plant mass to be really effective.
 
Anyone know if swedish ivy would work? I don't care so much about nitrate removal, I just want a vining plant to drape across my 75g that isn't toxic. Philodendrons and pothos plants aren't really safe around small children (my nephews love my tanks).
 
AquariaCentral.com