What specific light do you have? I assume it is a two bulb T5HO light. Some of those would give way too much light for a 29 gallon tank, while a couple would give low medium light, unless they were a few inches above the top of the tank.
You would need to fertilize the tank water and/or the substrate to have much chance of growing any plants. Eco Complete does not contain NPK, the major nutrients plants need.
You probably have medium light, so you will need CO2 to keep the plants growing as fast as the light is driving them to grow. That is a desirable situation, where limiting the growth rate by under supplying any nutrient, including CO2, isn't desirable at all - algae often take over when that is the situation.