What is killing my Anacharis?

I have added Anacharis to my 55 gal twice to aid in my battle against green water. The first time I had been dosing Flourish Excel (because I think the green water is due, in part, to a lack of CO2), so I assumed that is what caused it to die. It wasn't until two days after it died (and fueled a huge algae bloom), that I read Excel kills Anacharis. But, I added another four bunches recently, and they all died the exact same way. Since last dosing Excel I had done two 75% and one 50% water changes, so I didn't think it would be a problem. Do you think there was still enough present to kill it? The only other thing I can think of is that I bleach dipped all of the Anacharis. I dipped them for 90 seconds in a 25:1 water:bleach solution. By everything I have read I thought this is a fairly weak dip. Does Anacharis have an amazingly low tolerance to bleach dips?

That must have been it then. If I get more I sure won't dip them in bleach then. It was crazy--one day they were fine, the next day I had leafless brown stems. The sad part is that I bought the Anacharis as part of my battle against green water, and their death only fueled it. Grrrrr!