They are not fast growers I have 2 one in a low tech 5 and another in a high tech 40. I have inert substrate and use root tabs. The one in the 5 only put out 3 ish leaves the past 2 months but it recently spawned a new smaller plant. The one in the 40 has put out 4 or 5 leaves but still pretty slow. Pretty plant if you have sufficient light to keep it pink.
CO2 is not a pill for the tank to swallow when problems arise. It is a completely different process, is complicated and brings with it a host of problems. I would be very cautious about "...getting some CO2.." as this can cause more troubles than it solves.