Nitrogen (N) is responsible making proteins for new tissue growth, especially leafy tissues such as water lily pads. Yellow or pale green leaves or pads are a sign of not enough nitrogen. If your plants have a lot of greenery and lack flowers, then they may be getting too much nitrogen.
Phosphorus (P) is important for root growth and the growing buds and flowers. It's part of the biological energy molecule, ATP that helps to turn energy from the sun into usable energy for your plants (ADP to ATP).
Potassium (K) plays a role in making carbohydrates as well as helping with resistance to diseases. It's a metabolic regulator helping to balance the biochemistry. Stunted plants may be low in potassium and produce fewer offspring.