Have you tried cutting off the one that opened, and grew roots, and planting it? Maybe doing that will cause the mother plant to put it's energy into the other "babies".
I would try cutting the one that has rooted, or better yet leave it on the mother plant, and root the new shoot into your substrate. In most cases a sword giving off runners isn't something I would cut I would bury the runner still attached. most plants that give off runners will continue to grow if just planted, and left attached. Than that plant will give off another runner, and so on. If you haven't already done so I would try plant tabs to feed the mother plant, or add flourish to the water which will also feed all the plants you may have. Your lighting seems to be enough. Keep an eye on the leaves, and if they start to get brown spots cut the light back.