Plant growth

The northwest corner of the tank started out as the "jungle" - relative to the rest of the tank, it was densely planted, with two large Echinodorus plants dominating the corner. Over times, I added more plants to the tank, and the ones that were there grew. Recently I noticed that the northwest corner of the tank is one of the more open areas, as the Echinodorus plants have grown taller, and the older leaves have died. Today I noticed that the larger one has produced a leaf that has emerged from the water and is not pressed right against the lid. At the same time, with the addition of free-floating Elodea and another fast-growing fine-leaved plant, the surface of the western half of the tank is pretty much covered with plants. Things are different on the eastern half of the tank, where the flow of water out of the filter keeps the surface waters clear of floating plants.