Giant Vallisneria (Vallisneria gigantea) is a tall, grass-like aquatic plant. It develops very wide, flat stems.
Giant val is a very hardy and easy to care for plant. It does not require any CO2, but should be fertilized consistently (as they are very fast growing plants). It prefers water temperatures in the mid-70's, and will tolerate medium lighting (although high lighting is optimal for fast growth). It will do well in either sand or gravel substrates.
(Photo credit "Reef to Rainforest Media")