[Zapins]

I third their observations - the more light the better for HC.

Also the richer the soil the better - I use black compost for emersed grown HC.

Even so, HC is a slow growing plant and can take weeks to fill in nicely in a setup. There is also usually a delay between when the HC is first planted and when it starts to grow. 3-6 weeks of delay isn't uncommon in my experience before the HC really gets going.

 

[Zapins]

Oh yes, CO2 definitely helps. I tried pressurized CO2 on the emersed culture and it worked out well.

 

[Zapins]

It will do very well

Just make sure it doesn't overheat especially being enclosed in a container (traps heat).