Emersed several "Nephthytis" plants into my 55 G tanks, along with the Aglaonema, Pothos and "Queen Marble" Philodendron. With the roots under the tank water and the leaves above to pick up the "ambient" light and CO2
, the tank is balanced between fish and plants. The "Ag" plants have multiple white blossoms, many more than I've seen on potted plants. The nitrogens produced by the fish are the best natural ferts I've ever used. The Flora Pride liquid from Tetra is very good too as a supplement.
The plants continue to purify the water and take in the wastes faster than the bacteria in the back up filtration. So, the nitrates are low. I guess it's not surprising the plants do a more thorough job of cleaning the water than I did when I was doing the large, weekly water changes. They've been on the job much longer.