Plant ID

[Martinspuddle]

pardon the terrible looking red root floaters

Nutrient level needs to come up a bit, hence poor growth and brown leaves.

[Isy]

Unless there were two species in that initial bundle and I managed by sheer coincidence to separate them exactly weeks into having them, I'm going to have to disagree with your verdict. It's the same species under different growing conditions. The small tank gets more fertiliser (Tropica Premium Nutrition) and stronger light. I sacrificed one of each, to get a better view on how many leaves there are per node. Cabomba has two, from what I've seen on pictures online, but both plants I have, have 10.
But I am happy to do the experiment to make sure it isn't some plant version of the parent trap. So I've pulled out the "whatever it ends up being" from the big tank and I'll let it grow it in the small tank, separated by the rotala. Unless the above scenario happened, they should, with a bit of time, end up the same again.

[Isy]

But yes on the nutrients! The Hygrophila is a bit pale on the fresh growth too, so a bit of iron (?) probably wouldn't go amiss. The pinpricks in the red root floaters tell me I need to up the potassium too... once payday comes around I'll get on that