Jaco, any plant will use up excess nutrients in the pond water. This type is a bonus as all the photosynthesis/respiration is above water level, so no oxygen depletion over-night or added PH swings. Also the plant and roots are floating so no soil medium needed. Only thing needed if your wise is to snap off any withering tubers/bulbs.
Gota stick a photo in, love um. Unculled hariwake.
Maurice.
