I will have Co2 once I flood it, but right now I'm only 1 month or so into a 3 month dry start. HC really needs Co2, I've heard. In a small tank like this you can probably get away with DIY though. You don't need a fast bubble rate.
Just be very very very very slow when you flood it off the side with a turkey baster. I got over eager with a plant bowl today and uprooted half the HC I spent 30 mins planting. Though I'm sure a 3 month dry start will lead to a much better root structure.