I had that purple leafed plant (or one that looked alot like it) and it never really grew, just attracted algae)
I was told it wasn't really an aquatic plant.
I took it out and got Indian Fern which is growing like mad and all the algae is gone! (so far so good)
I'd be interested to hear how you go with that plant in the long term. Do you know what it is called?
Tank will look great once the plants start growing, more plants!!!