I seem to have a lot more luck with semi-aquatic plants than aquatic plants. I had some anachris when I first started my tank and it died within a few weeks, all the leaves started to disintegrate except for a few little buds of new growth which seemed to be doing fine. I threw that out because I was impatient and bought ribbon plant, a semi-aquatic and it's been doing great. I also had some hornwort when I first started, but I think I killed that just from using it as cover in a QT tank. I dumped needles like crazy even when it was under proper lighting. I bought a mixed pot of plants, a few of which I think are proper aquatics and one of which I know is a semi-aquatic. Again, the semi-aquatic is doing wonderful, even with the algae competing with it. The full-aquatics are kind of disintegrating in the stems. I keep pulling out leaves that are attached by what look like threads where the stem should be. I bought a new bunch of anachris a few weeks ago and it died again. I finally gave up on it a few days ago and cut off the new growth that was thriving and just let it float in my tank. I think it's grown some, but that just might be me being hopeful.
My pH is pretty high, 8.2 on a good day, so I don't know if that affects the sorts of plants I can keep? I have good fluorescent lighting. I can't remember the kelvin rating, but it was within the range suggested to me last time I had plant problems.
My photoperiod is probably around 12-15hours, since the timer I bought for them is awful and unreliable and I leave the house at 7am every morning and rarely get back before 10pm. I'm going to assume that's where my algae problem came from too. If anyone knows of a good, reliable, easy to program timer, I would love to know. This one is Zilla brand, took forever to program, and just flat out doesn't cycle on and off. It's been in night mode (on, apparently, even though that's the opposite of what I programmed) for about a month now. It's just an expensive power strip with a clock anymore.
Ok, now I'm just tired, grumbly, and rambling. I'm going to go to sleep, so if anyone has any tips for me, I'd love to see them in the morning!