A question for all the plant gurus on this forum. I've noticed recently that some of my stem plants (particularly elodea) seem to be growing with a shorter stem length in between leaves. Very evident when looking at the plant as a whole, since the leaves near the bottom have (for example) half an inch of stem in between leaf layers whereas near the top, that space may be only half that. Is this a sign that I may be lacking some nutrient in my tank? Or do plants tend to do that if they are growing very fast? (the elodea in question has grown an inch in a few days). Any thoughts on this matter would be greatly appreciated.