One of my watersprites is taking over my tank with low light! (2wpg) I just add a little fert, no CO2. They grow fast and all the fish seem to love playing in it!
I have never had a problem gowing watersprite but with no ferts or co2 you might be better off using Hygrophila difformis (Water Wisteria).
Light - Medium - Very high
Temperature - 72 - 86 °F (22-30 °C)
Hardness - Very soft - Very hard
pH - 5-9
Growth - Fast
Demands - Easy
Hygrophila difformis is beautiful and undemanding. A plant for beginners which can help create a balance in the aquarium from the start. Its rapid growth helps prevent algae because the plant absorbs a great number of nutrients from the water. The shortage of micro-nutrients leads to pale leaves, which may be an indication that the aquarium needs fertilizer. In large aquariums its lobed leaves can create a distinctive group. In strong light, this plant can be trained to grow along the substrate with little trouble. Just put a stone down here and there on the stems until they take root. This is another one that needs regular pruning to keep short, but it makes a very pretty ground cover, and fills in very quickly.
I bought a plant at my LFS that was labeled "floating wisteria" and it grows really well! I have less than 2 wpg and no CO2. It looks like a giant lily pad now with roots that hang down half the length of the tank! It also produced lots of babies that I then put in my bigger tank. Would this be the same as water wisteria, just left floating instead of rooted?