If the lucky bamboo stalk is turning yellow from the bottom, over-fertilization is usually the culprit.
Change the water (use distilled water or evaporate the chlorine from the tap water first) and don’t feed the lucky bamboo for several weeks. You may have to remove the stalk that is yellow from the container. If you cut the stalk just above the yellow part (a about an inch above one of the growth rings) you can root the green part — discard the yellow part.