i see you've fallen prey to the same thing i have. too many plants, not enough time/knowledge to keep them all going.
I bet you had a few fast growers that out did the rest? happened to me in my 20g long too!
its not that great of a tank for fast growing stems unfortunately.
You are totally correct! My huge thing is not enough time! I have figured out that I don't really like spending the time on properly maintained stems! I'd just rather not keep them! Perhaps in the future just not at the moment!