they grows slow, and you are changing water too much. dont' change water, just add water to it, then it should be fine, my experience is that they thrive when you ignor them
lucky bamboo is a tropical plant, so no need to change water that often or care that intensively as u have described. It's supposed to thrive in low light conditions. About one to two inches of fresh water will be just fine. Change water every two weeks. No fertilizer is needed as lucky bamboo is very sensitive to salts(which may cause tip burn on the leaves). Btw,Legend has it that if your lucky bamboo grows, your luck will grow, too. As chinese new year is fast approaching,//best wishes:may