If you always assume any plant growth problems are because you don't have enough or consistent enough CO2, you will be right a lot more times than you will be wrong. Carbon is the primary building block for plants, so CO2 is the primary need they have to grow well. DIY CO2 is unlikely to give you either enough or consistent enough CO2 for a 29 gallon tank, unless you use multiple bottles, with staggered change times. And, 1-2 bubbles per second isn't likely to be enough for the light you have.
I'm assuming the 36 watt light is an AH Supply light kit. If so, you likely have high light intensity in the center of the tank, but the short bulb is likely to cause the intensity to be much lower at the ends of the tank.