Sometimes some floating plants do not do so well in one tank than it does in another even if its set up in the same room.
I have two tanks side by side, slightly different set ups, one has T8 lights and the otehr T5 and different substrate etc, but both at same temperature and same tap water etc, water lettuces grows real well in one tank but dies off in the other, silvania natans does terrible in one tank and flourishes in the other.
Could be down to a number of things, flow, lights, ferts and water quality. I tend to see what grows well and stay with that and if plant dies I take it out and replace with another specie and see how it fares, trial and error innit