This original post is old I know, but it has received some recent activity, I am sure Kevin who started this thread is long gone, and hopefully with a healthy plant, but I would look here if I had a sick LB, with the new activity. If I ran this website, I would have a disclaimer legally written up attached, there is so much incorrect information. Thankfully, most of it was written some time ago, and I will not be hauled out and publicly tarred and feathered. Sometimes you gotta speak up!

First of all, Sans (above) is very knowledgeable, and gives good clear suggestions as to where to start when figuring out why a plant is sick. Listen to only her, in this post please. not that she is the only one with good tips, but you are just receiving so many well intentioned but totally lethal suggestions. I am sort of surprised. I am going to hurt some feelings and be attacked by others, both of which I hate.

I just have to speak up, because this plant is not very unhealthy, and you have kept it in quite nice shape for a long time. Most LB's are tossed within a the first year, I would bet. Please.......Do not increase light to improve the yellowing of leaves. you will have yellow burnt leaves. The number one reason for yellowing leaves on most plant types is over watering. If you feel strongly you are not overwatering, trust that and look for the second reason most likely reason, TOO MUCH light. Can it be the summer sun has made the plant feel like it moved from Anchorage to the Sahara I would need more water if I was suddenly thrown into a desert, are you changing culture from winter needs to summer needsl .Does the room get Southern exposure Get it further from the window if it does. You say you have had this plant a couple of years Honestly, that is a long time for most to keep this plant looking so nice. Your Draceana is by far healthier than the 30 or more that I see every day at work, I have the only Lucky bamboo in the building that is happy. You have done well for two years. Of all the advice you can get, no one is better equipped to diagnose what adjustments will help your plant than you. Please listen to your own instincts, reread you original post. You had two guesses, and they are the best guesses to start with. I could tell you to change water on a schedule, , how to fert, but I don't know if you are already doing that or not. If I were to give specific advice, I would ask you google yellow dry leaves on Lucky bamboo, Lucky bamboo care, Native habitat for LB and so on. You don't have to become a plant nerd, but a little bit of this really helps. Pick some sights that are really reputable, no advice from sights with adds all over them, and no forums, if you are not sure you can spot good tips over bad ones. Just good research. Flower shops are not where I would start, and yet the best article I found for you is from a flower shop. After that, come back here. It is fun to learn what others did, There are so many posters here that are golden in being helpful and accurate with their suggestions. And some, not so much.

Here is part of a page with very good advice below, with link

The solution for too much sun is changing out the water and not fertilizing for a couple of months. Move the plant into a bright area without direct sunlight. Too much sun can cause yellowish leaves and splitting, which can be fixed with trimming them off at an angle.

and the link: http://www.flowershopnetwork.com/blog/?s=lucky+bamboo You may have to copy and paste, Link would not insert. I looked at a lot of pages for you, just poke around.

My best advice to you is trust your own instincts a bit more, I think you have a greener thumb than you realize.